EXTREME HIGH temperatures can be fatal. While mercury is rising towards record temperatures across several parts of the state, this first study in rural India finds a direct association between temperatures above 39 degree Celsius and non-infectious disease mortality.
Pune-based researchers, Vijendra Ingole and Dr Sanjay Juvekar, conducted the study to investigate both heat and cold effects on total mortality, infectious disease mortality, non-infectious disease mortality and external causes of death between 2003 and 2012 using verbal autopsy data of the Vadu Health and Demographic Surveillance System (HDSS) in Western India. ‘Verbal Autopsy’ is a collection of post-mortem information about a deceased individual through questionnaire or interview of household members, friends and others (including health care workers) who cared for the person at home or are familiar with the circumstances of the death. The findings have been published in the December 2015 issue of the International Journal of Environment Research and Health.
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Heat-related mortality and morbidity can occur through direct and indirect pathways, through heat exhaustion or heat stroke, renal insufficiency, acute cerebrovascular disease and exacerbations of pulmonary disease. According to the International Disaster Database (EM-DAT), in India, 10,389 deaths were caused by extreme high and low temperature between January 1990 and March 2014, Juvekar told The Indian Express.
The largest disease group was non-communicable diseases, mainly consisting of acute myocardial infarction, stroke, actual renal failure, asthma, and chronic ischaemic heart disease. There were 1,175 deaths in this group, Ingole said. “We observed a strong significant immediate impact of high temperature (57% increase) on deaths by non-infectious diseases,” added Ingole.
There is evidence that not only heat strokes, but also cardiac diseases and renal impairment are associated with heat . The population in Vadu HDSS was highly affected by non-infectious disease, such as cardiovascular diseases, respiratory diseasesand kidney disease (acute renal failure). Secondly, total mortality was 33% higher during heat events, he explained. Ingole said if someone has cardiovascular risk and is exposed to heat, then the chances of dying is more. “Our study findings suggest that men of working age are more vulnerable to hot temperatures, which suggests that agricultural and industrial workers are in high risk zone,” he added.
The Vadu HDSS is a member centre of the International Network for the Demographic Evaluation of Populations and Their Health. “We have used data of 2,302 deaths for which verbal autopsy was performed. For each deceased, age, gender, cause of death, and date of death were obtained. International classification of Diseases—10 codes were assigned by a physician and were grouped into four classes of diseases: infectious, non-infectious, external causes of death and unspecified causes of death. Daily maximum temperature data were acquired from the Indian Meteorological Department.