Research

Published and Forthcoming Papers

1. Furuya, Shiro, and Jason M. Fletcher. Accepted. “Retirement Makes You Old? Effect of Retirement on Biological Age.” Demography.

2. Furuya, Shiro, Fengyi Zheng, Qinogshi Lu, and Jason M. Fletcher. 2024. “Separating Scarring Effect and Selection of Early Life Exposures with Genetic Data” Demography 61(2): 363-392. doi: 10.1215/00703370-11239766.

3. Furuya, Shiro, Jihua Liu, Zhongxuan Sun, Qiongshi Lu, and Jason M. Fletcher. 2023. “The Big (Genetic) Sort? A Research Note on Migration Patterns and Their Genetic Imprint in the UK.” Demography 60(6): 1649–1664. doi: 10.1215/00703370-11054960.

4. Furuya, Shiro, Jihua Liu, Zhongxuan Sun, Qiongshi Lu, and Jason M. Fletcher. 2023. “Understanding Internal Migration: A Research Note Providing an Assessment of Migration Selection with Genetic Data.” Demography 60(6): 1631–1648. doi: 10.1215/00703370-11053145.

5. Furuya, Shiro, and Jia Wang. 2023. “The Long Shadow: Early-Life Adversity and LaterLife Loneliness in the United States.” The Journals of Gerontology: Series B 78(2):370–382. doi: 10.1093/geronb/gbac164.

6. Furuya, Shiro, and Jason M. Fletcher. 2022. “Early Life Environments and Cognition in Adulthood: New Evidence Using a Semiparametric Approach and Quantile Regression.” Social Science and Medicine-Population Health 19:101251. doi: 10.1016/j.ssmph.2022.101251.

7. Wu, Yuchang, Shiro Furuya, Zihang Wang, Jenna E. Nobles, Jason M. Fletcher, and Qiongshi Lu. 2022. “GWAS on Birth Year Infant Mortality Rates Provides Evidence of Recent Natural Selection.” Proceedings of the National Academy of Sciences 119(12). doi: 10.1073/pnas.2117312119.

8. Furuya, Shiro, Jason M. Fletcher, Zijie Zhao, Zhongxuan Sun†, and Qiongshi Lu. 2022. “Detecting Genetic Heterogeneities in Response to Trauma: The Case of 9/11.” *Social Science and Medicine-Mental Health 2:100044. doi: 10.1016/j.ssmmh.2021.100044.

9. Furuya, Shiro, and James M. Raymo. 2021. “Living Arrangements, Intergenerational Support, and Married Women’s Subjective Well-Being.” Asian Population Studies 18(1):87–107. doi: 10.1080/17441730.2021.1975396.

Papers Under Review

• Furuya, Shiro, and James M. Raymo. “Loneliness at Older Ages in Japan: Variation in Lonely Life Expectancy and the Role of Social Isolation.” (Revised and resubmitted to Population Research and Policy Review (second round)).
  • Abstract: Loneliness is the focus of growing media, policy, and research attention, but remains an understudied dimension of social inequality among demographers and other social scientists. This study examines the duration of exposure to loneliness at older ages in Japan, the world’s oldest country. Analyses conceptually and methodologically account for the related, but distinct, concept of social isolation. Combining life tables from the Human Mortality Database with individual data from the National Survey of Japanese Elderly, we used Sullivan’s method to calculate lonely life expectancy (LLE) and isolation-adjusted LLE by sex, region of residence, and educational attainment. LLE at age 60 was 2.4 to 2.7 years for Japanese men and 4.1 to 5.0 years among women. These sex differences became less pronounced after accounting for social isolation, especially family-related aspects of isolation. We found no clear regional or educational differences in (isolation-adjusted) LLE. In contrast to public perceptions of growing loneliness, we found that (isolation-adjusted) LLE is relatively short among older Japanese and has not increased over time.
• Furuya, Shiro. “Cumulative Effect of Retirement on Mortality.”
  • Abstract: Mortality effects of retirement in prior work are rarely informative (statistically significant). However, this does not necessarily indicate the absence of mortality effect of retirement. While prior works assumed an instantaneous change in mortality risk upon retirement, the mortality effect of retirement may cumulatively evolve upon retirement. Using the Health and Retirement Study and fuzzy regression discontinuity and kink designs, I estimated mortality effects of retirement and retirement duration. Consistent with prior work, I find no evidence for a sudden jump in mortality risk at retirement. By contrast, I find that each additional year of retirement duration increases mortality risk by 0.9 percentage points, suggesting growing inequalities in mortality risk between retirees and non-retirees. The positive, cumulative mortality effect of retirement at the Social Security eligibility age has important implications for an increase in the Social Security eligibility age, population health, and welfare programs to support older people in the U.S.

Manuscripts in Preparation

• Furuya, Shiro. “Consequences of Retirement on Divorce.”

• Furuya, Shiro, Sungsik Hwang, and Felix Elwert. “Consequences of Educational Homogamy, Hypergamy, and Hypogamy: Evidence from Mass Randomized Marriage.”

• Furuya, Shiro, Boyan Zheng, and Jason M. Fletcher. “Unpacking the Black Box in the Long Arm of Childhood: Mediating and Moderating Roles of Education”