Association between Indoor Temperature in Winter and Serum Cholesterol: A Cross-Sectional Analysis of the Smart Wellness Housing Survey in Japan

Abstract

Issuance of the WHO Housing and health guidelines has paralleled growing interest in the housing environment. Despite accumulating evidence of an association between outdoor temperature and serum cholesterol, indoor temperature has not been well investigated. This study examined the association between indoor temperature and serum cholesterol. Methods:We collected valid health checkup data of 2004 participants (1333 households), measured the indoor temperature for 2 weeks in winter, and divided participants according to whether they lived in a warm (average bedroom temperature ≥ 18℃), slightly cold (12-18℃) or cold house (＜12˚C). The relationship between bedroom temperature and serum cholesterol was analyzed using multivariate logistic regression models, adjusting for demographics, lifestyle habits and the season in which the health checkup was conducted, with a random effect of climate areas in Japan. Results:The sample sizes for warm, slightly cold, and cold houses were 206, 940, and 858, respectively. Compared to those in warm houses, the odds ratio of total cholesterol exceeding 220 mg/dL was 1.83 (95%CI: 1.23-2.71, p=0.003) for participants in slightly cold houses and 1.87 (95%CI: 1.25-2.80, p=0.002) in cold houses. Similarly, the odds ratio of LDL/non-HDL cholesterol exceeding the standard range was 1.49 (p=0.056)/1.67 (p=0.035) for those in slightly cold houses and 1.64 (p=0.020)/1.77 (p=0.021) in cold houses. HDL cholesterol and triglycerides were not significantly associated with bedroom temperature. Conclusion:Besides lifestyle modification, improving indoor thermal environment through strategies such as installing high thermal insulation and appropriate use of heating devices may contribute to better serum cholesterol condition.

Role of housing in blood pressure control: a review of evidence from the Smart Wellness Housing survey in Japan

“…We named this effect "cold debt", with reference to sleep debt [55], which is a state of chronic sleep deprivation leading to physical and mental disorders. In addition to the results presented in this review, the SWH survey revealed that the of residents with high cholesterol was larger in colder homes [56]. A long-term risk of progression of arteriosclerosis is therefore present.…”

Impact of the COVID‐19 pandemic on the glycemic control in people with diabetes mellitus: A retrospective cohort study

“…In addition to people with diabetes mellitus, those with other chronic diseases such as hypertension, cardiovascular diseases, and chronic obstructive pulmonary disease also tend to show exacerbation of their disease condition in the winters [36][37][38] . Hormonal changes, such as the activity of the hypothalamic-pituitary-adrenal axis, serum cortisol levels, and levels of vitamin D are putative factors involved in such aggravation 39,40 . Not only hormonal changes, but even changes in the ambient temperature, humidity, hours of sunshine, eating habits, activity levels, and seasonal events such as Christmas, year end and New Year parties could also lead to worsened glycemic control 20,41,42 .…”

The Association between Indoor Temperature and Hypercholesterolemia

“…Hyperlipidemia is an important risk factor for CVDs. In Umishio et al's research, inadequate indoor temperature (＜18 ℃) was positively associated with hyperlipidemia 1) . Unlike outdoor temperature, the indoor temperature is an adjustable factor.…”

“…In this issue of the Journal of Atherosclerosis and Thrombosis, Umishio et al report the association between indoor temperature in winter and serum cholesterol based upon a cross-sectional analysis of the Smart Wellness Housing Survey in Japan 1) . The indoor temperatures of 2004 participants (1333 households) were measured for 2 weeks in winter, and they were divided into three categories according to average bedroom temperature: 206 warm houses (≥18 ℃), 940 slightly cold houses (12 ℃-18 ℃) and 858 cold houses ( ＜12 ℃).…”