Swiss Tropical and Public Health Institute, Kreuzstrasse 2, CH-4123, Allschwil, Switzerland.
University of Basel, Basel, Switzerland.
BMC Public Health. 2023 Feb 8;23(1):291. doi: 10.1186/s12889-023-15128-6.
Cardiovascular diseases (CVDs), the leading cause of death worldwide, are sensitive to temperature. In light of the reported climate change trends, it is important to understand the burden of CVDs attributable to temperature, both hot and cold. The association between CVDs and temperature is region-specific, with relatively few studies focusing on low-and middle-income countries. This study investigates this association in Puducherry, a district in southern India lying on the Bay of Bengal, for the first time.
Using in-hospital CVD mortality data and climate data from the Indian Meteorological Department, we analyzed the association between apparent temperature (T) and in-hospital CVD mortalities in Puducherry between 2011 and 2020. We used a case-crossover model with a binomial likelihood distribution combined with a distributed lag non-linear model to capture the delayed and non-linear trends over a 21-day lag period to identify the optimal temperature range for Puducherry. The results are expressed as the fraction of CVD mortalities attributable to heat and cold, defined relative to the optimal temperature. We also performed stratified analyses to explore the associations between T and age-and-sex, grouped and considered together, and different types of CVDs. Sensitivity analyses were performed, including using a quasi-Poisson time-series approach.
We found that the optimal temperature range for Puducherry is between 30°C and 36°C with respect to CVDs. Both cold and hot non-optimal T were associated with an increased risk of overall in-hospital CVD mortalities, resulting in a U-shaped association curve. Cumulatively, up to 17% of the CVD deaths could be attributable to non-optimal temperatures, with a slightly higher burden attributable to heat (9.1%) than cold (8.3%). We also found that males were more vulnerable to colder temperature; females above 60 years were more vulnerable to heat while females below 60 years were affected by both heat and cold. Mortality with cerebrovascular accidents was associated more with heat compared to cold, while ischemic heart diseases did not seem to be affected by temperature.
Both heat and cold contribute to the burden of CVDs attributable to non-optimal temperatures in the tropical Puducherry. Our study also identified the age-and-sex and CVD type differences in temperature attributable CVD mortalities. Further studies from India could identify regional associations, inform our understanding of the health implications of climate change in India and enhance the development of regional and contextual climate-health action-plans.
心血管疾病（CVDs）是全球首要死因，对温度敏感。鉴于气候变化趋势的报告，了解高温和低温对 CVD 造成的负担非常重要。CVD 与温度之间的关联具有区域性，仅有相对较少的研究关注中低收入国家。本研究首次在印度孟加拉湾的本地治里地区调查了这种关联。
我们使用住院 CVD 死亡率数据和印度气象局的气候数据，分析了 2011 年至 2020 年期间本地治里的表观温度（T）与住院 CVD 死亡率之间的关联。我们使用病例交叉模型和二项式似然分布相结合的分布式滞后非线性模型，捕捉 21 天滞后期内的延迟和非线性趋势，以确定本地治里的最佳温度范围。结果表示为归因于热和冷的 CVD 死亡率分数，相对于最佳温度定义。我们还进行了分层分析，以探索 T 与年龄和性别、分组和综合考虑以及不同类型的 CVD 之间的关联。进行了敏感性分析，包括使用拟泊松时间序列方法。
我们发现，本地治里 CVD 的最佳温度范围是 30°C 到 36°C。冷和热非最佳 T 与整体住院 CVD 死亡率的风险增加有关，导致 U 形关联曲线。累积起来，多达 17%的 CVD 死亡可归因于非最佳温度，其中归因于热（9.1%）的负担略高于冷（8.3%）。我们还发现，男性对较冷的温度更敏感；60 岁以上的女性对热更敏感，而 60 岁以下的女性则受到热和冷的双重影响。与脑血管意外相关的死亡率与热相关，而与冷相关，而缺血性心脏病似乎不受温度影响。
高温和低温都会导致热带本地治里归因于非最佳温度的 CVD 负担。我们的研究还确定了年龄和性别以及 CVD 类型对温度归因于 CVD 死亡率的差异。印度的进一步研究可以确定区域关联，增进我们对印度气候变化对健康影响的理解，并加强区域和背景气候健康行动计划的制定。
