New York City heat can be a killer -- literally. Between 2000 and 2011, it claimed 13 lives a year, researchers found.
During that time period there were also an annul average of 447 emergency department visits and 152 hospitalizations for heat-related illnesses, according to Kathryn Lane, MPH, of the New York City Department of Health and Mental Hygiene, and colleagues.
Heat-related deaths were more common among patients who were obese (48%), had evidence of cardiovascular disease (75%), were female and 65 or older (26%), were male and ages 35 to 64 (34%), and had no air conditioner (88%), they wrote online in Morbidity and Mortality Weekly Report.
The authors noted that heat waves are the most common cause of death due to extreme weather in the U.S., and that non-heat wave temperatures are also responsible for additional deaths. In New York City, "summer temperatures ... are increasing, with longer and hotter heat waves projected into the next century and beyond," they cautioned.
The researchers assessed risk factors and vulnerable populations in New York City for heat illness and heat stroke through data from hospitals, death certificates, and medical examiner records from 2000 to 2011. Data were also collected on comorbid conditions, patient characteristics, presence of a working air conditioner at the illness site, and environment where the illness occurred.
Electronic medical records were collected through the New York Statewide Planning and Research Cooperative System (SPARCS), which were used to identify cases of heat illness that were labeled as excessive heat due to weather conditions. Deaths in the records were labeled as due to exposure to excessive natural heat or heatstroke and sunstroke. Deaths related to man-made heat exposure were excluded.
Nearly half of all heat deaths (45%) over the 12-year period occurred during heat waves in 2006 and 2011. In 2006, temperatures rose over 90°F over 10 days, while the peak heat index over the 4-day 2011 heat wave rose above 110°F.
Cardiovascular disease was the most common condition among patients hospitalized or who died due to heat (64% and 55%), followed by diabetes (23% and 13%), substance abuse (14% and 11%), and mental health conditions (24% and 11%).
By demographics, older women and men ages 35 to 64 had the highest prevalence of heat-related hospitalization and death. Neighborhoods with 10% to 20% poverty had the highest rates of death and hospitalization, each at or above 35%. Patients predominantly experienced heat-related illness and heat stroke death at home (48% and 80%, respectively).
Among those who died at home, all the cases involved a residence where there was either no air conditioner or the air conditioner was not working or not in use.
Among those with known BMI, nearly half of those who died of heat-related causes were obese (48%), while 24% of those who died were normal or underweight and 29% were overweight.
"Rising summer temperatures from climate change, a growing older adult population, and the increasing prevalence of obesity and chronic disease might increase the number of serious heat illnesses and deaths in New York City," the report concluded, adding that access to air conditioning and observation of family members who may be at-risk for heat-related illness were paramount in combating injury and death from summer heat.
They also recommended city-dwellers stay hydrated, visit cooling centers or other public air conditioned spaces when air conditioning is not available, and make use of pools, cool showers, and baths to beat the heat.
The authors found their study was limited by missing data on place of heat-related illness, absent data on additional heat-related illness-associated hospital care for other conditions, and may underestimate obesity in the population.
The authors declared no conflicts of interest.
- Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Morbidity and Mortality Weekly ReportSource Reference: Lane K, et al "Heat illness and deaths -- New York City, 2000-2011" MMWR 2013; 62(31): 617 - 621.