Comparative analysis of multimorbidity prevalence and lifestyle factors among older adults in frigid versus non-frigid zones of China

Multimorbidity, defined as the coexistence of at least two chronic diseases in an individual, exhibits spatial heterogeneity in its association with lifestyle factors across different climatic zones. Older adults in frigid zones–defined as areas where the average temperature in the coldest month is ≤ -10℃, or where daily mean temperatures ≤ 5℃ persist for ≥ 145 days per year-face distinct environmental exposures compared to those in non-frigid zones. Nevertheless, few studies have explored multimorbidity and lifestyle differences between frigid and non-frigid zones. This study aims to: (1) identify sociodemographic, lifestyle, and regional factors linked to multimorbidity in Chinese older adults and further to compare them across zones; and (2) assess lifestyle diversity related to multimorbidity in each zone. A total of 10,619 participants aged ≥ 60 years were included from China Health and Retirement Longitudinal Study (CHARLS) collected in 2020. All participants met the inclusion criteria were classified with reference to the 2016 GB50176 climate standard for frigid zone and non-frigid zone. Chi-square test, regression analyses, and subgroup analysis were used to describe and analyze risk factors and difference in multimorbidity between frigid zone and non-frigid zone among Chinese older adults. (1) The prevalence of multimorbidity among older adults is significantly higher in frigid zone (72.69%) than in non-frigid zone (65.63%) and the national level (66.32%). (2) Living zones and lifestyles have association on multimorbidity in older adults. (3) The effect of Internet use on multimorbidity in the older adults demonstrated significant heterogeneity in terms of living zone(I2 = 66.1%). Much attention should be paid to older adults with multimorbidity residing in frigid zone. Especially, targeted interventions for unhealthy lifestyle in frigid zone and non-frigid zone among older adults to decrease multimorbidity prevalences and their catastrophic consequences. For older adults in frigid zone. In parallel, study indicated that appropriate sleep duration, reducing problematic internet use, smoking cessation and alcohol restriction and other healthy lifestyle may contribute to multimorbidity prevention among older adults especially in frigid zone.