Short-, Medium-, and Long-Term Temperature and Sudden Cardiac Death in a Cohort of US Women

Sudden cardiac death (SCD) is an important contributor to the global burden of cardiovascular disease. Previous studies have reported an association with extremes in temperature in the hours and days leading up to SCD, but there has been little investigation focusing on the months and year before an SCD event. Therefore, the objective of this study was to investigate the relationship between short-, medium-, and long-term temperature and SCD.

Temperature predictions using 800-m Parameter-Elevation Regressions on Independent Slopes Model data were used to estimate monthly moving average temperature. Data on temperature were appended to each Nurses' Health Study participant's geocoded residential addresses. SCD cases were determined on the basis of medical record review and next-of-kin reports. Time-varying Cox proportional hazards models were used to assess the association between exposure 1- and 12-month moving averages of temperature and SCD. Individual risk factors, socioeconomic status, and cardiovascular comorbidities were considered as confounders in the final models.

Over the follow-up period, there was a total of 428 definite and 36 probable SCD cases among the 118 636 participants. One- and 12-month moving average temperatures were inversely associated with SCD in the basic, risk factor, and fully adjusted models. For example, in the parsimonious individual risk factor model with definite cases only, per interquartile range (15.27 °C for the 1-month moving average temperature, 4.72 °C 12-month moving average temperature) increase in temperature, the hazard ratios for definite SCD were 0.58 (95% CI, 0.44-0.77) for the 1-month and 0.76 (95% CI, 0.66-0.88) for the 12-month moving average.

After controlling for risk factors and cardiovascular morbidities, lower temperatures were associated with SCD. This study demonstrates that short-, medium-, and long-term cold temperature also play an important role in SCD.