Population-level seasonality in cardiovascular mortality, blood pressure, BMI and inflammatory cells in UK biobank

Abstract

Introduction: The risk of mortality from cardiovascular disease (CVD) is higher in wintertime throughout the world, but it is not known if this reflects annual changes in diet or lifestyle, or an endogenous photoperiodic mechanism that is sensitive to changes in day length.

Methods: Phenotypic data on cardiometabolic and lifestyle factors were collected throughout a 4 year time period from 502,642 middle-aged participants in UK Biobank. To assess the impact of seasonal environmental changes on cardiovascular risk factors, we linked these data to the outdoor temperature and day length at the time of assessment. Self-reported information on physical activity, diet and disease status were used to adjust for confounding factors related to health and lifestyle.

Results: Mortality related to CVD was higher in winter, as were risk factors for this condition including blood pressure, markers of inflammation and body mass index (BMI). These seasonal rhythms were significantly related to day length after adjustment for other factors that might affect seasonality including physical activity, diet and outdoor temperature.

Conclusions: The risk of CVD may be modulated by day length at temperate latitudes, and the implications of seasonality should be considered in all studies of human cardiometabolic health.

Key messages

• In this cross-sectional study in UK Biobank, we report annual variations in cardiovascular risk factors and mortality that were associated with day length independent of environmental and lifestyle factors.

• These seasonal changes in day length might contribute to annual patterns in cardiovascular disease and mortality.

Keywords:

• Blood pressure
• cardiovascular disease
• inflammation
• life style
• obesity
• risk factors
• seasons
• temperature

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Acknowledgments

This research was conducted using data from the UK Biobank. This resource was established by the Wellcome Trust, Medical Research Council, Department of Health, Scottish Government and the Northwest Regional Development Agency, with additional funding from the Welsh Assembly Government and the British Heart Foundation. All authors had full access to all the data and take responsibility for its integrity and the accuracy of the analysis.

Disclosure statement

The authors report no conflicts of interest.

Additional information

Funding

CAW was funded by a Lord Kelvin Adam Smith Fellowship from the University of Glasgow.