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

<b><i>Background:</i></b> 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. <b><i>Objective:</i></b> We examined the relative contributions of social and behavioural factors on the differences in survival among older people in Japan and England. <b><i>Methods:</i></b> We used data from the Japan Gerontological Evaluation Study (JAGES; <i>n</i> = 13,176) and the English Longitudinal Study of Ageing (ELSA; <i>n</i> = 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. <b><i>Results:</i></b> 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. <b><i>Conclusion:</i></b> 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.

<b><i>研究背景：</i></b> 人口快速老龄化给医疗与社会照护服务带来了严峻挑战。目前针对老年人群生存状况的跨国比较研究较为匮乏，且在这类研究中，预期寿命全球最长的日本往往未被纳入。<b><i>研究目的：</i></b> 本研究旨在探讨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。<b><i>研究方法：</i></b> 本研究采用日本老年学评估研究（Japan Gerontological Evaluation Study, JAGES；<i>n</i> = 13,176）与英格兰纵向老龄化研究（English Longitudinal Study of Ageing, ELSA；<i>n</i> = 5,551）的数据，分析基线后长达9.4年的全因死亡率。通过构建拉普拉斯回归模型（Laplace regression models），估算第15生存百分位数的差异。<b><i>研究结果：</i></b> 随访期间，ELSA队列中31.3%的女性与38.6%的男性死亡，而JAGES队列中该比例分别为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队列女性的生存时间较ELSA队列女性长318.8天，男性则长131.6天。对于男性而言，家庭型社会关系使JAGES队列男性的生存时间较ELSA队列男性多出105.4天；而友谊型社会关系不足则使JAGES队列男性的生存时间较ELSA队列男性缩短45.4天。当前未吸烟的状态对JAGES队列女性（延长197.7天）与ELSA队列男性（延长46.6天）的生存均有正向贡献；而较低的身体质量指数（Body Mass Index, BMI）则使JAGES队列女性的生存时间缩短129.0天，男性缩短212.2天。<b><i>研究结论：</i></b> 与英格兰老年人群相比，日本老年人群寿命更长，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，英格兰队列的生存优势则来源于更低的低体重发生率、男性更优质的友谊型社会关系以及更低的吸烟率。