Ambient temperature and risk of cardiovascular hospitalization: An updated systematic review and meta-analysis

Abstract

The association between temperatures and risk of cardiovascular mortality has been recognized but the association drawn from previous meta-analysis was weak due to the lack of sufficient studies. This paper presented a review with updated reports in the literature about the risk of cardiovascular hospitalization in relation to different temperature exposures and examined the dose-response relationship of temperature-cardiovascular hospitalization by change in units of temperature, latitudes, and lag days. The pooled effect sizes were calculated for cold, heat, heatwave, and diurnal variation using random-effects meta-analysis, and the dose-response relationship of temperature-cardiovascular admission was modelled using random-effect meta-regression. The Cochrane Q-test and index of heterogeneity (I(2)) were used to evaluate heterogeneity, and Egger's test was used to evaluate publication bias. Sixty-four studies were included in meta-analysis. The pooled results suggest that for a change in temperature condition, the risk of cardiovascular hospitalization increased 2.8% (RR, 1.028; 95% CI, 1.021-1.035) for cold exposure, 2.2% (RR, 1.022; 95% CI, 1.006-1.039) for heatwave exposure, and 0.7% (RR, 1.007; 95% CI, 1.002-1.012) for an increase in diurnal temperature. However no association was observed for heat exposure. The significant dose-response relationship of temperature - cardiovascular admission was found with cold exposure and diurnal temperature. Increase in one-day lag caused a marginal reduction in risk of cardiovascular hospitalizations for cold exposure and diurnal variation, and increase in latitude was associated with a decrease in risk of cardiovascular hospitalizations for diurnal temperature only. There is a significant short-term effect of cold exposure, heatwave and diurnal variation on cardiovascular hospitalizations. Further research is needed to understand the temperature-cardiovascular relationship for different climate areas.

Ambient temperature and risk of cardiovascular events at labor and delivery: A case-crossover study

“…The literature generally suggests that exposures to both high and low temperatures are associated with cardiovascular events in non-pregnant populations around the world (Basu, 2009; Bhaskaran et al, 2012; Ha et al, 2014; Honda et al, 2016; Phung et al, 2016; Sartini et al, 2016; Wang et al, 2016; Yang et al, 2015) with potentially higher sensitivity among Blacks women, those with lower socioeconomic status, the elderly, and young children (Basu, 2009); but data among pregnant women are currently lacking. One large international multicenter case-control study among reproductive age women ages 15 to 49 showed that each 5°C decrease in monthly average temperature was associated with a 7% and 12% increase in hospital admission rates for stroke and acute myocardial infarction, respectively; and these effects were more prominent within one month of exposure (Chang et al, 2004).…”

The cold effects on circulatory inflammation, thrombosis and vasoconstriction in type 2 diabetic patients

“…Massive previous studies have linked cold weather with hospitalization and mortality from CVD (Kysely et al, 2009;Phung et al, 2016). But the precise pathophysiologic mechanisms of the impact of cold temperature on CVD remain speculative.…”

“…Exposure to cold has been worldwide associated with cardiovascular outcome (Kysely et al, 2009;Phung et al, 2016). Previous studies have observed increased risks of myocardial infarction (Bhaskaran et al, 2010), stroke (Fustinoni et al, 2013) and hypertension (Jansen et al, 2001) when temperature declines.…”

Effects of extreme temperatures on cardiovascular emergency hospitalizations in a Mediterranean region: a self-controlled case series study

“…Some reviews showed a weak effect of hot temperatures on cardiovascular diseases in the elderly [6], and in general population [10], but such effect was not found in a meta-analysis by Turner et al 2012 [9]. Another meta-analysis by Phung et al aligned [11] with Turner et al regarding the lack of effect of hot temperatures, but reported a positive association of heatwaves with cardiovascular hospitalizations.…”

“…Extreme cold increases the risk of cardiovascular hospitalization not only during cold spells but also some days after the cold spell episode occurred [7–11]. Studies assessing the impact of cold spells on health have mainly been conducted in cold-weather regions of Russia [16], Canada [12], China [13], USA [14] and United Kingdom [15].…”