biostudies-literatureLv YNIA NIH HHSNational Institutes of HealthNIH HHSNational Natural Sciences Foundation of China2145-2154https://www.ebi.ac.uk/biostudies/studies/S-EPMC11212828biostudies-literatureUnknown45(24)<h4>Background and aims</h4>Emerging evidence has raised an obesity paradox in observational studies of body mass index (BMI) and health among the oldest-old (aged ≥80 years), as an inverse relationship of BMI with mortality was reported. This study was to investigate the causal associations of BMI, waist circumference (WC), or both with mortality in the oldest-old people in China.<h4>Methods</h4>A total of 5306 community-based oldest-old (mean age 90.6 years) were enrolled in the Chinese Longitudinal Healthy Longevity Survey (CLHLS) between 1998 and 2018. Genetic risk scores were constructed from 58 single-nucleotide polymorphisms (SNPs) associated with BMI and 49 SNPs associated with WC to subsequently derive causal estimates for Mendelian randomization (MR) models. One-sample linear MR European heart journalBody mass index, waist circumference, and mortality in subjects older than 80 years: a Mendelian randomization study.PMC11212828P30-AG02871682222063P30 AG0287168202503081941023Guo YLv YRen YYu QWu BDeng LWei YWang JShi XQiu YKraus VBZhou JXu LTong SLi CCui XZeng YChen CYin ZLi XYe LMao CLu HZhang YLuo YGao XXu ZfalseBody mass index, waist circumference, and mortality in subjects older than 80 years: a Mendelian randomization study.<h4>Background and aims</h4>Emerging evidence has raised an obesity paradox in observational studies of body mass index (BMI) and health among the oldest-old (aged ≥80 years), as an inverse relationship of BMI with mortality was reported. This study was to investigate the causal associations of BMI, waist circumference (WC), or both with mortality in the oldest-old people in China.<h4>Methods</h4>A total of 5306 community-based oldest-old (mean age 90.6 years) were enrolled in the Chinese Longitudinal Healthy Longevity Survey (CLHLS) between 1998 and 2018. Genetic risk scores were constructed from 58 single-nucleotide polymorphisms (SNPs) associated with BMI and 49 SNPs associated with WC to subsequently derive causal estimates for Mendelian randomization (MR) models. One-sample linear MR 2024-01-01T00:00:00Z2024 Jun2025-07-26T03:06:56.687Z2025-07-08T03:10:50.403ZS-EPMC112128283862630610.1093/eurheartj/ehae206