COLD WEATHER KILLS MANY MORE THAN HOT WEATHER
Cold weather kills 20
times as many people as hot weather, according to an international study
analyzing over 74 million deaths in 384 locations across 13 countries. The
findings, published in The Lancet, also reveal that deaths due to moderately hot or
cold weather substantially exceed those resulting from extreme heat waves or
cold spells.
"It's often
assumed that extreme weather causes the majority of deaths, with most previous
research focusing on the effects of extreme heat waves," says lead author
Dr Antonio Gasparrini from the London School of Hygiene & Tropical Medicine
in the UK. "Our findings, from an analysis of the largest dataset of
temperature-related deaths ever collected, show that the majority of these
deaths actually happen on moderately hot and cold days, with most deaths caused
by moderately cold temperatures."
The study analysed
over 74 million (74,225,200) deaths between 1985 and 2012 in 13 countries with
a wide range of climates, from cold to subtropical. Data on daily average
temperature, death rates, and confounding variables (eg, humidity and air
pollution) were used to calculate the temperature of minimum mortality (the
optimal temperature), and to quantify total deaths due to non-optimal ambient
temperature in each location. The researchers then estimated the relative
contributions of heat and cold, from moderate to extreme temperatures.
Around 7.71% of all
deaths were caused by non-optimal temperatures, with substantial differences
between countries, ranging from around 3% in Thailand, Brazil, and Sweden to
about 11% in China, Italy, and Japan. Cold was responsible for the majority of
these deaths (7.29% of all deaths), while just 0.42% of all deaths were
attributable to heat.
The study also found
that extreme temperatures were responsible for less than 1% of all deaths,
while mildly sub-optimal temperatures accounted for around 7% of all deaths --
with most (6.66% of all deaths) related to moderate cold.
According to Dr
Gasparrini, "Current public-health policies focus almost exclusively on
minimizing the health consequences of heat waves. Our findings suggest that
these measures need to be refocused and extended to take account of a whole
range of effects associated with temperature."
Writing in a linked
Comment, Keith Dear and Zhan Wang from Duke Kunshan University, Kunshan,
Jiangsu, China say, "Factors such as susceptibility or resilience have not
been included in the analysis, including socioeconomic status, age, and
confounding air pollutants…Since high or low temperatures affect susceptible
groups such as unwell, young, and elderly people the most, attempts to mitigate
the risk associated with temperature would benefit from in-depth studies of the
interaction between attributable mortality and socioeconomic factors, to avoid
adverse policy outcomes and achieve effective adaptation."
Comments
Post a Comment