Pavilion Publishing and Media Ltd
Blue Sky Offices Shoreham, 25 Cecil Pashley Way, Shoreham-by-Sea, West Sussex, BN43 5FF, UNITED KINGDOM
Tel: +44 (0)1273 434 943
Email: [email protected]
Warmer temperatures during the night-time in summer may be linked with an increase in cardiovascular death in men in their early 60s, according to a study published in BMJ Open.
Research shows that sustained periods of higher temperatures often coincide with surges in deaths and hospitalisations due to cardiovascular conditions, but findings related to age and gender have been inconsistent.
So, researchers from the University of Toronto, Canada, set out to examine the link by analysing data from two databases in the UK and the USA, as well as meteorological data.
They compared to data from the the Office for National Statistics on adult deaths attributed to CVD for the months of June and July in every year between 2001 and 2015 in England and Wales and then compared this to official USA data for King County, Washington.
They chose King County as it is also a sea-facing region, at parallel latitude to England and Wales, with comparable land-ocean atmospheric properties and similarly low prevalence of residential air conditioning. The US data, however, only included men.
CVD rates declined substantially over time but a considerable residual risk persisted
In England and Wales, there were more than 39,900 CVD deaths, 68.9% of whom were men. In King County, 488 deaths were recorded.
In England and Wales, after allowing for certain variables, a 1°C rise in the usual summer night-time temperature was associated with a 3.1% increase in the risk of CVD mortality among men aged 60 to 64, but not older men or either women age groups.
In King County, a 1°C rise was associated with a 4.8% increased risk of CVD mortality among those aged 65 and under, but not in older men.
While the CVD rates declined substantially overall in both regions due to the uptake of primary and secondary preventive therapies, the researchers say a considerable residual risk persisted.
In England and Wales, CVD rates remained more than 50% higher in adults aged 65 to 69 than in those aged 60 to 64 years. This was worrying, they added, because in recent years, populous regions such as the ones studied had experienced a proportionate rise in night-time rather than daytime summer heat intensity.
The results invite “preventive population health initiatives”
The researchers acknowledge some limitations to the study including the unavailability of 15-year sex- and age-specific weekly outcome and exposure data by district or city level, which might have identified stronger associations between night-time summer heat and CVD mortality in populous urban regions.
However, they also note that the study is strengthened by its large population size data and use of reliable mortality and meteorological data.
They said: “The present findings should stimulate similar investigation of exposure and event rates in other populous mid-latitude to high-latitude regions.
“Considering the growing likelihood of extreme summers in Western USA and UK, our results invite preventive population health initiatives and novel urban policies aimed at reducing future risk of CVD events.”