Until the last few years, lightning injuries have been the second most common cause of storm-related death in the United States (lightning is now behind flash floods and tornados). [1, 2, 3] Although National Oceanic and Atmospheric Administration (NOAA) data showed as many as 3,000 deaths and nearly 10,000 casualties from lightning in the years from 1959-1994, the annual death rate has decreased to less than 0.1 case per million for the last five years, owing to public education by the media and the members of the Lightning Safety Week team.  While it is highly likely that all US deaths are recorded as a result of improved media coverage, the actual number of lightning casualties may be higher, because up to 50% may go unreported.  Nevertheless, in most years, lightning kills more people each year in the United States than hurricanes, volcanoes, and earthquakes combined.  (See Epidemiology and Etiology.)
Far more injuries and deaths occur in tropical and subtropical developing countries (see Epidemiology and Etiology), and newspaper reports frequently list multiple injuries and deaths in each event. Complicating the increased risk people in these countries have because of higher lightning density (lightning strikes/km2/year), lightning-unsafe housing, and greater everyday exposure are the folk beliefs that may prevent adequate prevention and mitigation. People in many countries believe in two kinds of lightning: "natural lightning" and "man-made lightning" that can be called down by witches or can be prevented with charms, herbs, or burying something under a structure as it is being built. [5, 6] In Zambia, it is believed that wearing the color red attracts lightning. Others believe that anyone injured by lightning has been cursed, shunning them and their family. Families may believe their only recourse is to move and start over in a village where their history is unknown. 
For most thunderstorms, 70-90% of lightning strikes are intracloud or from cloud to cloud. From 10-30% of lightning can be cloud to ground (CG), depending on the storm. Lightning strikes the earth more than 100 times each second and 8 million times per day. Worldwide, approximately 50,000 thunderstorms occur per day that may result in forest fires, injury to animals and people, and/or damage to electrical and communications lines and electronics, leading to millions of dollars in downtime for businesses. Everyone is a potential victim.
In the United States, cloud-to-ground lightning strikes occur approximately 30 million times each year.  Lightning strikes in the United States are most common in Florida, the Atlantic coast, and along the southeastern coast of the Gulf of Mexico.  The National Weather Service (NWS) estimates that 100,000 thunderstorms occur in the United States each year. Lightning is evident in all thunderstorms. The danger of lightning may not be apparent to an individual because lightning can strike 10 miles or more away from the rain of a thunderstorm.  (See Epidemiology.)
Lightning starts with short (30-50 m) spurts of static energy in a cloud. The lightning retreats back to its origin, refills the original channel, and branches at the end of the original channel to make a second generation of 30- to 50-m channels. Lightning continues with the retreats and new generations until the charge is either expended (intracloud lightning) or randomly works its way downward as a CG flash. 
Any object near the intense electrical field of a thundercloud will have an opposite charge induced in it, be it a television tower, a tree, a person, or a blade of grass. Multiple upward leaders of current rise from these objects. Most do not contact the main lightning channel but may have sufficient energy to cause significant injury (Cooper upward streamer). Eventually, the downward leader may join one or more of the upward streamers to complete the lightning channel. At that point, a return stroke fills all of the branches and the lightning becomes visible. Lightning has more than one ground contact about 30-50% of the time.
Only three factors predispose to a lightning hit: height of an object, isolation, and "pointiness," which is not a factor with people. However, while lightning has a tendency to hit the tallest object, this 30- to 50-m radius from the last branch point means that tall objects, such as a mountaintop half a mile away, a television tower 300 yards away, a tree 75 yards away, or even the goal posts on a football field, are outside the range for protecting anyone (ie, the field's goalposts are unlikely to protect someone standing in the middle of a football field if lightning is coming down over the person's head). There are multiple instances and videos of strike points to cars passing tall telephone or electrical poles and other hits where lightning seems to “ignore” the height rule.  (See Etiology and Prevention.)
With all these data, it must be realized that while lightning science strives to describe and explain it, mostly in a statistical manner, these are not rules governing its behavior. Lightning is capricious and random, and any individual strike may defy common public assumptions.
Although most injuries occur outdoors, a few people are injured indoors every year from contact injuries with plumbing or landline telephone–mediated strikes. [11, 12] While use of cell phones, iPods, and other portable electronic devices may change the pathway of lightning around a person, it does not increase the risk of injury except by distracting the individual from paying attention to warning signs, such as storm clouds and thunder. In fact, the worldwide availability of cell phones is offering an ideal opportunity for texted or tweeted severe weather warnings and other public education. [6, 13]
The most important characteristic features of lightning injuries are multisystem, primarily neurologic, injuries and widely variable severity. This article discusses the physics of lightning and the pathophysiology and treatment of lightning injuries.  Because persons struck by lightning have a better chance of survival than persons who experience cardiopulmonary arrest from other causes, resuscitation for persons struck by lightning must be instituted immediately, followed by a comprehensive treatment program of the other systemic manifestations.  (See Prognosis, Presentation, and Treatment.)
Types of injuries
Few individuals experience the full energy of a lightning strike because only about 3-5% of injuries are from a direct strike.  Most of the energy is mediated by other factors, including the ground, a tree, or other object that, once hit, transmits the energy to the person. In fact, fewer than half of affected persons have signs of burns or any other marks. When burns do occur in developed countries, they are usually superficial. In addition to electrical injury, many may suffer concussive blunt force trauma if they are close to the strike point.  Internal burns or deep burns, such as occur with high-voltage electrical injury, are rare.
In developing countries, severe burns are reported much more frequently. It is unclear if these are sampling bias, if reports are inflated by journalists who hear the story several times removed from the incident and expect the victims to be “charred beyond recognition,” if the mechanisms and physical damage are somehow different, or if the injuries appear to be more severe owing to delayed access to good medical care.  Ninety percent of sub-Saharan housing, usually mud brick with thatch or sheet metal roofs, is not lightning safe. Keraunoparalysis, a temporary paralysis after lightning injury that may last for minutes to hours, may keep even healthy individuals from escaping their home as the overhead thatch, ignited by lightning, burns and falls on them. 
Myoglobinuria is rarely caused by lightning, whereas cardiac and respiratory arrest, vascular spasm, neurologic damage, and autonomic instability are more common.  Blunt force injuries may occur from falling, being thrown by muscle contractions, or barotrauma from the explosive force of a nearby lightning strike.  Occasionally, a person may receive secondary shrapnel-like injuries by being hit by pavement or bits of an exploded tree. 
Lightning strikes are primarily a neurologic injury that affects all three components of the nervous system: central, autonomic, and peripheral.
Classification of lightning injuries
Because exposure to the effects of lightning can be so variable in mechanism and intensity, it is useful to characterize lightning injuries as mild, moderate, or severe.
Mild lightning injury is rarely associated with superficial burns, but persons struck often report loss of consciousness, amnesia, confusion, tingling, and numerous other nonspecific symptoms. Lightning burns are invariably superficial and have little or no deep-tissue damaging effects. Provided the patient is stable and there are no contraindications such as chest pain, hypotension, or continuing mental status changes, many of these patients can be released home with reliable caretakers. Since there is little known at this time that can be done to mitigate the outcome and sequelae, there is usually little benefit to hospitalization.
Moderate lightning injury may cause seizures, respiratory arrest, or cardiac standstill, which spontaneously resolves with resumption of normal cardiac activity. Much of the symptomatology mirrors that of mild lightning injury, except superficial burns are much more common, both initially and in a delayed fashion. These patients may have lifelong symptoms of brain injury, chronic pain, irritability, and sleep disorders. There is still little that hospitalization can offer these patients except careful monitoring for acute complications connected to the initial manifestations.
Patients with severe lightning injury usually present with cardiopulmonary arrest, often complicated by a prolonged period in which they did not receive CPR. The delay may be because the individuals are in an isolated location when injured or because of the myth that the person retains an electrical charge, making him or her dangerous to touch. Survival is rare in this group unless a bystander begins CPR immediately. There have been rare cases of recovery from this more severe group but usually only after prolonged ICU and rehabilitative care.
Additionally, as noted above, victims in developing countries may have more severe burns resulting from keraunoparalysis and burns by secondary fire.
Physics of lightning
Lightning is a natural atmospheric electrical discharge that occurs between regions of net positive and net negative electrical charges. It is dependent on a complex interaction of updrafts, moisture, atmospheric instability, temperature, and other factors. Readers with a special interest in this are referred to the NOAA article Understanding Lightning for a thorough but understandable discussion with animations.
There are two basic types of lightning: cloud-to-cloud or intracloud (CC) and cloud-to-ground (CG). A lightning flash is initiated by an electrical breakdown between the positive and negative charge regions in a cloud. Sixty to 90% of lightning is intracloud. When the flash turns towards the ground, a barely visible downward leader descends in regular steps, typically 30-50 m long at intervals of 0.05 ms in a downward, branching fashion toward the ground. This initial flow of electricity, the leader stroke, reaches the ground in approximately 20 ms. The diameter of the stepped leader ranges from a few centimeters to a few meters, depending on what parameter is measured. Within the leader is a current-carrying core 1-2 cm in diameter.
As the branching process nears the ground, an upward discharge, termed the upward leader, completes the path of ionization approximately 30-50 m above the ground. At this moment of attachment, the cloud is short-circuited to the ground, and the major electrical discharge, a luminous return stroke of high current, occurs. Following the initial stroke, secondary leader and return strokes frequently occur.
See Lightning Safety for many other interesting facts about lightning.
Air that is crossed by lightning is heated rapidly, and the cylindrical column expands at supersonic speeds. Within 1-2 meters, the shockwave decays to a sound wave called thunder. Thunder comes from the entire lightning channel length, producing a mixture of different tones that are further modified as it spreads outward. Thunder rarely is heard at distances greater than 10 miles because of such factors as terrain, atmospheric temperature, wind shear, large intervening structures, and urban noise.
The power of lightning is awesome, an estimated 10,000-200,000 amperes (A) of current and 20 million to 1 billion volts. A current of 100,000 A can shift blocks of stone weighing 5 tons, and rocks weighing 50 pounds may be thrown 20 yards or more.
Types of lightning
CG lightning, described earlier, is the most frequent type of lightning and accounts for human injuries. Another type, sheet lightning, travels within a cloud and gives the cloud the appearance of a white sheet. “Heat lightning” is a misnomer for lightning that does not appear to be connected with rain and is usually far enough away to make a wonderful show. It is equally as dangerous as any other form of lightning and can turn into deadly cloud-to-ground lightning just as easily.
Several rare forms of lightning are ribbon and bead lightning. These are forms of cloud-to-ground discharge with a flash consisting of several strokes. Ribbon lightning occurs when the channel is blown perpendicular to the line of sight by the wind, displacing subsequent strokes. Consequently, the flash appears as a ribbon of several strokes. In bead lightning, the main lightning flash breaks into luminous sections, or beads, as the light intensity of the channel decays.
The most rare and mysterious form of lightning is ball lightning.  A mix of fire and electricity concentrated in a fireball with a diameter of 10-30 cm, ball lightning usually appears suddenly, even in indoor conditions, during a thunderstorm. It moves quickly for several meters, can change direction, and ultimately disappears sometimes soundlessly and other times with a pop or larger explosive sound. It has a life span of several seconds, and its color is quite variable but most commonly described as white, yellow, or orange.
The mechanism of cardiac arrest is not known and may be from direct depolarization of the myocardium; damage or shock to the electrical systems of the heart, carotid body, atrioventricular (AV) node, or other parts; or damage to the autonomic nervous system or other mechanisms.
It has been theorized that lightning depolarizes the entire myocardium at once, causing a single systolic contraction followed by a variable period of asystole (primary cardiac arrest). Cardiac activity may return spontaneously, first at a markedly bradycardic rate and then slowly increasing in speed. Rhythm may deteriorate from apnea resulting from paralysis of the respiratory center in the medulla or from other mechanisms that are unknown at this time.
Lightning injuries versus common electrical injuries
Although lightning injuries can be classified as a special case of electrical injuries, the physics of lightning is far different from man-made electricity, leading to significant differences in the pathophysiology and injury patterns. 
Lightning cannot be classified as either direct current or alternating current. Lightning is not "scalable"—one cannot use his or her experience and knowledge of 110-volt lines or high-voltage injuries to predict what lightning will do. The physics of lightning is incredibly complex and substantially different from the physics of generated electricity. Unlike generated electricity, which is a voltage phenomenon, lightning is a current phenomenon. Once attachment occurs (completion of the lightning pathway to ground), any voltage in the lightning goes to zero.
Although the vast majority of news and witness reports credit “direct” strikes, this is often because of second-hand reporting, seeing only a portion of an unexpected and incredibly fast incident, lack of knowledge of other mechanisms, over-dramatization, and other factors.  Less than 5% of lightning deaths are caused by direct strike. The vast majority of lightning injuries are from indirect mechanisms.  The other 95% of deaths are caused as lightning first hits another object (eg, tree, tower, ground) and then side flashes to a nearby person or passes through the roots, ground, pipes, wires, or other object on its pathway to the person. Fewer than half of all survivors have any signs of burns or marks on their skin, probably because the lightning energy is mitigated by these primary targets and transit through other materials before it reaches the person.
Probably the most important difference between lightning and high-voltage electrical injuries is the duration of exposure to the current, which also affects the path it takes. While the energy from lightning may flow through the person for an incredibly brief period (4-6 ms), usually the vast majority of lightning energy flashes around the person's body surface, often vaporizing sweat or rainwater to cause secondary steam burns rather than primary lightning burns. 
Lightning has only brief contact with skin, and, in most instances, the contact is too brief to burn the skin substantially. Entry and exit are inappropriate terms to apply to lightning injuries.  In addition, because of this “flashover” effect by lightning, myoglobinuria, renal failure, and compartment syndrome occur much more rarely from lightning injury than from commercial electrical injury. When current does enter the body, almost every organ system is vulnerable. A wide variety of complications can result from damage to these organ systems, and specific sequelae dictate the choice of therapy.
Lightning also has a shockwave component that can cause injury. 
Although it is nearly impossible to document which mechanism of lightning injury was involved in a particular case, such knowledge or speculation of the mechanism of injury has no effect on patient care.
Types of human lightning strikes
Direct strike (approximately 3-5% of injuries)
Side splash from another object (approximately 30% of injuries)
Contact voltage from an object that is struck and conducts electricity to the site of touch, such as plumbing or wiring (approximately 1-2% of injuries)
Ground current effect as the energy spreads out across the surface of the earth when lightning hits a distance away from the person (approximately 40-50% of injuries)
Upward leader that does not connect with the downward leader to complete a lightning channel (approximately 15-20% of injuries)
Blunt trauma if a person is thrown and barotrauma from being close enough to experience the explosive force of lightning 
Direct strikes occur to victims who are outside. Although not always fatal, direct strikes are associated with high morbidity because they frequently involve the head. Lightning strikes near the head may enter the eyes, ears, and mouth to cause multiple problems. While most would conclude that a direct strike would be more likely to end in death than other mechanisms, there is no research or epidemiologic data to support this to date.
More commonly, the victim is struck by a flash discharge from another struck object. This type of splash injury occurs, for example, when someone seeks shelter beneath a tree, picnic shelter, or other object that is struck by lightning. A portion of the lightning may jump from the object struck to the victim. Splash injury also occurs from person to person when several people are standing close together.
Contact injury occurs when a person is touching an object that is either directly hit or splashed by lightning, such as indoor plumbing or wiring, hard-wired phones, a metal fence, bleachers, or other objects struck by the lightning.
Lightning also can result in harmful ground current that causes mass casualties in fields or other open areas. The severity of ground current injuries tends to decrease with distance from the point of the lightning strike.
Energy sufficient to cause death or injury also occurs in an upward streamer that can be induced in a person near a thunderstorm. 
Blunt trauma occurs when a person is thrown by a massive opisthotonic contraction caused by the lightning strike. There have been reports of both superficial and internal injury from blast effect. [31, 21, 32]
The primary risk factor for lightning injury is the failure to acknowledge that lightning poses a threat. Lightning safety and injury prevention is not convenient. It involves being aware of weather predictions, sometimes changing plans, and proactively planning evacuation to safer areas and the time to reach them. No place outside is safe when thunderstorms are in the area. [19, 33, 34, 35, 36, 37, 38] While safe areas are within a few yards in 98% of the time in developed countries, in developing countries, there may be no safe place within many miles for people to evacuate to.
Lack of knowledge of lightning danger and the mechanisms of injury also contribute to the risk. Many people try to finish one more inning or wait until rain begins before seeking shelter. This is often too late because lightning can travel as far as 10 miles in any direction from the thunderstorm clouds. The interstrike distance, depending on the local terrain and geography, may be as far as 5 ±5 miles, for a range of 0-10 miles (and sometimes more) from the last stroke.
Despite popular belief, nothing attracts lightning. The primary physical factors that make an object statistically more likely to be struck are isolation, height, and narrowness of the tip of the object facing the cloud. Only the first 2 factors apply to people.
While lightning can be seen hundreds of miles away on the Great Plains or not at all in heavily forested areas, thunder usually cannot be heard more than about 10 miles away. By the time one hears thunder, one is already in danger and should be seeking a safer structure or fully enclosed metal vehicle. The following 3 themes correctly summarize all of lightning safety and are the basis for Lightning Safety Week:
- When thunder roars, go indoors! (to a substantial building or fully enclosed metal vehicle)
- No place outside is safe when thunderstorms are in the area.
- Half an hour since thunder roars, now it’s safe to go outdoors.
The only reason that cell phones and iPods are dangerous in thunderstorms is that they distract the individual from paying attention to the weather and hearing thunder, the primary warning signal for lightning (see Telephone injuries below).
Although lightning injuries during recreational activities tend to predominate in industrialized countries, work-related lightning injuries also occur but have decreased markedly as many industries have adopted lightning safety guidelines for their workers. In the last few years, the vast majority of those killed have been within a few feet of safety. [2, 39] See Lightning Safety for statistics on the last decade of deaths in the United States by year, state, sex, age, and activity.
In the United States, certain geographic areas such as mountains, parts of Florida and the Gulf Coast, the Eastern Seaboard, and the major river valley areas of the Midwest are more prone to lightning because of weather patterns, moisture content of the air, and updrafts.
Around the world, the tropical and subtropical areas have far more lightning, less substantial housing, and, consequently, many more lightning injuries and deaths. [40, 41, 42] In developing countries with more labor-intense agrarian societies, the proportion of work-related injuries and deaths is probably higher. [43, 44]
Deaths inside buildings are rare in the United States and are usually to the infirm who are unable to escape secondary fires.  In general, being inside a substantial, habitable building such as a house, library, or school is one of the safer areas to seek shelter. The increased safety is credited, in part, to the fact that these structures tend to have plumbing and wiring in them, acting as a Faraday cage to transmit any electricity around the inhabitants. [33, 34, 37, 38]
Unfortunately, it is also true that lightning may hit or hit near a structure or recreational facility and be transmitted into the building through the plumbing, electrical wiring, emergency medical service (EMS) or fire dispatch radio, or other routes. This includes facilities with indoor pools, which should be evacuated using the same rules as outdoor pools. Individuals should avoid touching plumbing or objects that are electrically hard-wired to the structure's electrical system, including telephones, computers, and electronic games wired to televisions and computers.
Taking shelter in any structure that includes the word shelter (eg, bus shelter, sun shelter, park shelter, golf shelter, rain shelter) generally provides no protection. To date, national lightning-protection building codes (National Fire Protection Association: NFPA 780) address only physical protection of shelters but do not describe code to ensure the safety of people using them. Many believe that these structures may substantially increase the risk of lightning injury by increasing the functional height of the individuals standing under them, by increasing the risk of a side flash or ground current from a transmitted strike in structures with a lightning protection system, or by other mechanisms too long to go into in this discussion.
Being inside a fully enclosed metal vehicle is a very safe place because electricity will flow along the outside of any metal structure that it hits, not because of the miniscule effect of rubber composite tires. While being inside a vehicle when it is hit has been likened to "being inside a garbage can where someone threw two cherry bombs" and may be quite unpleasant, there has never been a substantiated electrical injury to a person inside a vehicle unless that person was touching a handheld radio hard-wired to the car’s lightning rod (antenna) or some similar connection to the outside.
As landline telephones have become less frequently used, indoor injuries from hard-wired telephones has substantially decreased. Hard-wired telephones become the conduit for the lightning charge to enter or to escape from a structure (and the person).  Although the telephone system may be grounded adequately for electrical surge protection, lightning energy surge is much too fast and strong for typical grounding and surge protection systems to be effective and reaches the person before the circuit breaker or other protection can be effective.
Injuries to persons using telephones or telephone headsets, such as those who take phone orders, used to be common but have decreased substantially now that wireless systems are more in use.
Older, portable phones, seldom used now in the United States, were a rare source of lightning injury to people standing within a yard or so of the base station or charger. Those injuries were caused by the lightning jumping from the charger to anything close by and had little to do with the phone the person was carrying.
No lightning danger is inherent to cellular phones. Although many reports of lightning injuries involve people who are using cellphones, these reports represent the ubiquity of cellphone usage and of their users' inattentiveness to weather conditions and have nothing to do with the phones themselves. Although it is theorized that cell phones or wearing earbuds or wires around the head may change the pathway of the lightning once a person is injured, they do not attract lightning. Conversely, since 90% of the world's population has access to cell phones, it may be possible to use them as a primary way of warning people in developing countries where forecasting and nowcasting are not available and weather reports are not easily accessed. 
In the past, acoustic injury was possible from the loud static noise in the earpiece of early portable phones, but to date, acoustic damage involving cellular phones has not been reported. 
In the United States and northern hemisphere, thunderstorms and lightning are most common from June through September. Lightning strikes usually occur in the afternoon and evening, coinciding with times when people are active and outdoors. Hikers, campers, and other outdoor sports enthusiasts most often sustain lightning injuries. Lightning injuries are more common in rural or exposed environments than in the city, where high buildings have metal frames and lightning-protection devices. In the past 5 years, the majority of deaths have been to individuals who were within a few feet of safety and doing routine things, including mowing the lawn or going outside of a store to get better phone reception.  Because lightning deaths have been decreased so drastically by public education, [20, 46, 47, 48, 49, 50] only the outliers remain. In particular, boating and fishing have recently shown a disproportionate number of fatalities. 
In tropical and subtropical countries, lightning deaths may occur at any time of year but are more common during the rainy seasons. In developed countries, “safe” areas are usually all metal enclosed vehicles, homes, or other substantial buildings because of the wiring and plumbing in the walls, which tend to channel any lightning energy through the walls to ground. Unfortunately, risk of death or injury from lightning is much higher for most developing countries because of much higher lightning density; greater exposure from labor-intense work practices such as farming, tending animals, and growing rice; long unprotected distances to walk to school, work, or markets; and the lack of safe areas to seek shelter. [36, 41, 44, 51, 52, 53, 54, 55, 56, 57, 58, 59]
Many homes are simple huts or rondavels with thatched or metal sheet roofs, so that entire families are at risk at all times, even when they are sleeping. Unlike developed countries where injuries and deaths are usually isolated and individual, multicasualty incidents are common in developing countries, whether in open-air church meetings, sporting events, classrooms, or homes. 
Lightning may strike as far as 10 miles in any direction from a thunderstorm, before the rain starts, or while the sky above is still clear. At least 10% of lightning hits when blue sky is visible. [33, 34, 38, 60] The most dangerous times for lightning injury are when the person underestimates the likelihood of being hit (ie, before the storm or at the apparent end of the storm).
Occurrence in the United States
For the past 40 years, lightning has consistently been the second largest storm-related killer in the United States,  with 45-50 persons killed annually by lightning. From 2000-2006, the estimated annual rate of deaths attributed to lightning strikes was 0.2 per million people. [46, 51, 62] Since 2010, deaths from lightning have gone to third place behind tornado deaths, in large part because of a decade of public education by the media and the Lightning Safety Week team. In 2013, only 23 deaths from lightning were reported in the United States, for a rate of 0.06 deaths per million population.
Traditional sources of lightning injury data (the National Center for Health Statistics and Storm Data) systematically underestimate the number of fatalities by 28-42%. [10, 63] One reason is that much of the older data are taken from newspaper accounts using clipping services to catch them, so if people struck by lightning do not make the news, they are not entered into the statistics. Newspaper reports have been a major source of national statistics on lightning deaths for many years. In the last 10 years, search engines such as Google have supplemented or replaced clipping services for collection of lightning fatality data by the National Climate Data Center’s (NCDC’s) Storm Data and Lightning Safety Week (LSW) committee. 
As for using medical data to catalog injuries or deaths, most survivors of lightning strikes do not need to be admitted to a hospital and, as a result, do not show up in medical data banks. Moreover, many survivors do not seek immediate medical care and only come to the attention of medical personnel when they seek care for effects of the shock that have not resolved within a few days after their injury. Because injuries are so infrequently reported compared with fatalities, a rule of thumb developed from studies is that injuries occur about 10 times more often than do fatalities. 
In the United States, most injuries occur between May and September. The National Center for Health Statistics has documented that the majority of US deaths by lightning strike occur in the South and the Midwest, with Florida and Texas usually leading the list. [46, 62]
In 2005, Adekoya and Nolte used data from both the National Centers for Health Statistics multiple-cause-of-death tapes and the Census of Fatal Occupational Injuries, which is maintained by the US Bureau of Labor Statistics, to investigate the epidemiologic characteristics and annualized rates of lightning-related deaths for the United States. 
From 1993-2000, 374 struck-by-lightning deaths were recorded, for an average annualized rate of 0.23 deaths per million persons. Incidents in the South and the Midwest accounted for the majority of fatalities (286 deaths, 75%; with the greatest number of deaths in Florida [49 deaths] and Texas [32 deaths]). From 1995-2002, 1 of every 4 struck-by-lightning deaths was work-related (129 deaths; average annual rate of 0.12 deaths per million workers), with agriculture and construction industries accounting for the most fatalities at 44 and 39 deaths, respectively. Fatal occupational injuries were greatest in Florida (21 deaths) and Texas (11 deaths). As found in many other studies, incidence rates were higher for males and people aged 20-44 years. 
Almost all prior studies have looked at lightning injuries per state and not by geographic features or population centers. A novel and interesting study by Ashley and Gilson mapped deaths from 1959-2000 reported from multiple databases by location of occurrence to create a spatial map. 
The map revealed an urban theme with high fatality counts clustered along population centers and lower counts scattered across rural areas. The highest counts were noted along central and eastern Florida and a corridor paralleling Interstate Highway 95 from Washington DC, Baltimore, Philadelphia, and New York City. Overall, metropolitan areas in Florida showed the highest counts, the New York/Atlantic area the second, and the Chicago area the third highest clusters. In returning to a state analysis, when adjusted for area, 4 of the top 5 normalized fatality rankings by state were in the Mid Atlantic and Northeast, with Florida being the fifth state in the count. 
Another way to cluster injuries and direct prevention strategies is by looking at where the greatest number of thunderstorms occur: the South; Rocky Mountain area; Gulf and Atlantic Coasts; and the Ohio, Mississippi, and Hudson River valleys. Obviously, injury prevention efforts should be maximized in the areas of most historical risk, while at the same time being watchful of changing patterns. Specialized risk areas such as wilderness recreation and water have not been analyzed by population and other tight epidemiologic methods but seem to pose high risk based on viewing of the data and newspaper reports.
The most common days of injury in the United States are Saturdays and Sundays, probably reflecting the recreational activities on the weekends. The most common time of day to be injured by lightning is from noon to 6 pm, with 6 pm to midnight following, related to not only when thunderstorms occur but also to when people are most likely to be outdoors. [10, 46, 65]
Lightning is much more common near the equator. Increased risk is due to labor-intensive work practices; insubstantial housing; long unprotected distances that people must travel to work, school, or market; and lack of metal vehicles.
Several papers have been published with different methodologies for predicting lightning deaths worldwide. [65, 39, 66, 67, 68, 69] One paper estimated total annual fatalities to be about 24,000, and annual injuries are estimated to be about 240,000 for the tropical and subtropical areas of the world, where lightning is most common and the economies tend to be more subsistent, agrarian, and labor-intensive than they are in the more developed and temperate climates. [10, 51] In general, lightning injuries and deaths decrease in any country as the economic system, urbanization, and housing improve, not only because direct numbers of persons exposed to lightning decrease but also as housing that contains plumbing and wiring providing protection becomes more prevalent. 
Compiling and recording statistics in individual countries is a challenge because they often lack a good reporting system.  Fortunately, more and more researchers are investigating and reporting on injuries in their countries to reveal patters and educate governments to the need for injury prevention. [44, 41]
A new report has linked geographic information system (GIS) locations of known injuries to lightning-density maps in the United States.  If this technique can be validated in a developing country where injury statistics are well known, such as Colombia,  it may be a very useful tool to focus injury prevention efforts in parts of Africa, Asia, and South America, where risk is high but fatality data and location are largely unavailable or inaccurate.
Race-, sex-, and age-related demographics
No relationship to race is known to exist.
In a US study, data from 1959-1994 indicated that males were 4.6 times more likely to be killed and 5.3 times more likely to be injured by lightning than were females. This was not because of any physiologic differences but was considered to be a consequence of males' increased exposure to potential lightning-strike situations, such as outdoor activities or work, as well as to males’ higher level of risk-taking behaviors. [10, 46] Fatality statistics with a 70-85% male component is consistent across countries and continents regardless of economic or meteorologic conditions.
Of deaths and injuries, 85% occur to persons aged 10-59 years. Few adults older than 60 years are injured. This is probably related to the decreased chances of exposure of this age group during outdoor recreation or employment. [10, 46]
Many individuals struck by lightning have permanent disabilities that affect their families and their ability to return to their previous work. In patients who have endured a more severe injury, the potential for permanent and debilitating neurologic and cardiac injury is greater.
However, no good long-term, controlled studies are available to indicate if lightning-related injuries improve or progress to more serious disabilities or to give stratified prognoses for different subgroups of survivors. As with other injuries, the longer a person has a symptom or sign, the more likely each is to be permanent.
Morbidity and mortality
In developed countries, lightning causes death in about 10% of its victims.  The ratio of deaths to injuries in developing countries is unknown. After a lightning injury, the probability of death is unrelated to sex, age, and the presence of trunk and arm burns. Factors that appear related to a fatal outcome are leg burns, head burns, and immediate cardiopulmonary arrest.  Some reports suggest as many as 74% of survivors of a lightning strike experience permanent injury and sequelae.  Other studies suggest the percentage with permanent injury is less; however, there continues to be controversy over the long-term effects in general.
Most lightning-associated deaths are caused by cardiac arrest. [73, 74, 75] Forensic physicians must consider lightning strike in the differential diagnosis of sudden unexpected death in persons found outside. [76, 77, 78] The most common minor injury reported is rupture of the tympanic membranes.  Superficial burns and eye injuries are frequently reported. [74, 72, 80, 81] The most common chronic sequelae reported are brain injury and chronic pain syndromes.
Lightning injuries differ from those resulting from high-voltage because lightning injuries usually do not cause significant tissue destruction along the path of grounding of the current. Blunt, concussive, and occasionally shrapnel-like physical injury may also accompany lightning injuries; therefore, medical personnel should also screen lightning victims for occult blunt trauma. [24, 74, 31, 32, 79]
Neuropsychological sequelae of lightning injury can cause significant morbidity.  Survivors of lightning injury report heightened anxiety states, hyperirritability, memory deficits, aphasia, sleep disturbance, attention deficit, deficits in working memory, and posttraumatic stress disorder. [83, 84] These symptoms also are found in patients with blunt head trauma, yet the sleep disturbance and memory difficulties are more severe than those caused by blunt brain injury.
Brain - Neurocognitive changes, sleep disturbance, personality change, seizures, learning disability, postconcussive-type headaches, nausea, attention deficit, distractibility, vestibular injury, pituitary and hypothalamic damage
Autonomic nervous system - Regulation of blood pressure and cardiac response (positive tilt test results, dizziness, hypertension), GI insult, impotence, sympathetically mediated pain syndromes
Peripheral nervous system - Chronic pain, sensory problems
Most patients with injuries caused by lightning regain consciousness. However, many patients injured by lightning experience transient motor paralysis (69% incidence of paralysis of the upper extremities and 30% incidence of paralysis of the lower extremities), usually sparing the ventilatory center. Paralysis from lightning injury is known as keraunoparalysis and is associated with sensory loss and cyanosis. Total resolution of paralysis usually occurs in minutes to days. If paralysis does not improve, other causes, such as direct spinal cord injury or musculoskeletal or blunt injury from a fall, should be suspected.
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