Supplementary Material for: Social and Behavioural Determinants of the Difference in Survival among Older Adults in Japan and England

Background: A rapidly ageing population presents major challenges to health and social care services. Cross-country comparative studies on survival among older adults are limited. In addition, Japan, the country with the longest life expectancy, is rarely included in these cross-country comparisons. Objective: We examined the relative contributions of social and behavioural factors on the differences in survival among older people in Japan and England. Methods: We used data from the Japan Gerontological Evaluation Study (JAGES; n = 13,176) and the English Longitudinal Study of Ageing (ELSA; n = 5,551) to analyse all-cause mortality up to 9.4 years from the baseline. Applying Laplace regression models, the 15th survival percentile difference was estimated. Results: During the follow-up, 31.3% of women and 38.6% of men in the ELSA died, whereas 19.3% of women and 31.3% of men in the JAGES died. After adjusting for age and baseline health status, JAGES participants had longer survival than ELSA participants by 318.8 days for women and by 131.6 days for men. Family-based social relationships contributed to 105.4 days longer survival in JAGES than ELSA men. Fewer friendship-based social relationships shortened the JAGES men’s survival by 45.4 days compared to ELSA men. Currently not being a smoker contributed to longer survival for JAGES women (197.7 days) and ELSA men (46.6 days), and having lower BMI reduced the survival of JAGES participants by 129.0 days for women and by 212.2 days for men. Conclusion: Compared to participants in England, Japanese older people lived longer mainly because of non-smoking for women and family-based social relationships for men. In contrast, a lower rate of underweight, men’s better friendship-based social relationships, and a lower smoking rate contributed to survival among participants in England.研究背景：人口快速老龄化给卫生与社会照护服务带来了重大挑战。当前针对老年人生存结局的跨国比较研究较为匮乏，且预期寿命位居全球之首的日本极少被纳入此类跨国比较分析中。 研究目的：本研究旨在探究社会与行为因素对日本与英格兰老年人群生存差异的相对贡献度。 研究方法：本研究采用日本老年学评估研究（Japan Gerontological Evaluation Study, JAGES；n=13176）与英格兰纵向老龄化研究（English Longitudinal Study of Ageing, ELSA；n=5551）的队列数据，分析基线后长达9.4年的全因死亡率情况。通过构建拉普拉斯回归模型（Laplace regression models），估算两组的第15生存百分位数差异。 研究结果：随访期间，ELSA队列中31.3%的女性与38.6%的男性发生死亡，而JAGES队列的死亡比例分别为19.3%的女性与31.3%的男性。在校正年龄与基线健康状态后，JAGES队列女性的生存时长较ELSA队列女性多出318.8天，男性则多出131.6天。家庭型社会关系使JAGES男性的生存时长较ELSA男性延长105.4天；而朋友型社会联结较少则使JAGES男性的生存时长较ELSA男性缩短45.4天。当前非吸烟状态可使JAGES女性（197.7天）与ELSA男性（46.6天）的生存时长更长，而较低的体质量指数（Body Mass Index, BMI）则使JAGES队列女性的生存时长缩短129.0天，男性缩短212.2天。 研究结论：与英格兰老年参与者相比，日本老年人的预期寿命更长，这主要得益于女性的非吸烟习惯与男性的家庭型社会关系。与之相对，英格兰参与者的生存优势则来自于更低的体质量不足发生率、男性更优质的朋友型社会联结以及更低的吸烟率。