Qiu, H., Tian, L., Ho, K., et al. (2015). Who is More Vulnerable to Death from Extremely Cold Temperatures? A Case-Only Approach in Hong Kong With a Temperate Climate. (Abstract only.) International Journal of Biometereology. 1-7.
The authors looked at 197, 680 deaths from natural causes, air temperature, and air pollution rates from November to April for 9 consecutive years. They found that individuals aged 85 and older, and those with cardiovascular diseases (including hypertensive diseases, stroke, congestive heart failure, chronic obstructive pulmonary disease (COPD), and pneumonia) had the greatest risk of death from exposure to extreme cold temperatures.