Objective To explore the correlation between physical activity, sleep and aging using a two-sample Mendelian randomization (MR) method. Methods The data through genome-wide association studies was summarized. The single nucleotide polymorphisms (SNPs) related to physical activity and sleep as instrumental variables was selected. The inverse variance weighting method was used for the main analyses, complemented by the weighted median method and MR Egger regression, and then sensitivity analyses were carried out in terms of multiplicity, heterogeneity and leave-one-out method. Finally, multivariate Mendelian methods were applied to eliminate confounders and find mediators. Results A total of two types of physical activity (strong physical activity, physical inactivity) and three sleep conditions (daytime naps, short sleep duration, adequate sleep duration) were found to have a causal relationship with frailty index (P<0.05), while physical inactivity was found to have a causal relationship with telomere length (P<0.05). A total of 167 SNPs were included in the analysis. Strong physical activity [correlation coefficient (β)=−1.26, 95% confidence interval (CI) (−1.60, −0.96), P<0.0001], adequate sleep duration [β=−0.17, 95%CI (−0.26, −0.09), P<0.001] were negatively correlated with the frailty index. Physical inactivity [β=1.47, 95%CI (0.85, 2.08), P<0.001], daytime naps [β=0.25, 95%CI (0.12, 0.39), P=0.0002], and short sleep duration [β=0.20, 95%CI (0.13, 0.27), P<0.0001] were positively associated with frailty index. Physical inactivity [β=−0.38, 95%CI (−0.69, −0.07), P=0.02] was negatively correlated with telomere length. Percentage body fat, body fat mass, waist circumference, body weight and body mass index partially mediated 25.52%, 23.52%, 10.08%, 17.6% and 10.08% of the effect between daytime naps and frailty index, respectively. Conclusion There is a causal relationship between physical activity, sleep, and aging.
ObjectiveTo systematically review the association between overweight, obesity, abdominal obesity, and cognitive impairment in the elderly. MethodsThe CNKI, WanFang Data, VIP, CBM, PubMed, Web of Science, Embase, and Cochrane Library databases were electronically searched for studies on the relationship between overweight, obesity/abdominal obesity, and cognitive impairment in the elderly from their inception to July 2024. Two researchers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. Meta-analysis was performed using Stata 15.0 software. ResultsA total of 38 studies involving 1 783 087 subjects were included. Meta-analysis results showed that compared with normal-weight individuals, overweight (OR=0.96, 95%CI 0.91 to 1.02, P=0.201) was not statistically significant in the risk of CI in the elderly. Obesity (OR=1.14, 95%CI 1.02 to 1.28, P=0.03) and abdominal obesity (OR=1.16, 95%CI 1.11 to 1.21, P<0.001) may be risk factors for CI in the elderly. Subgroup analysis was conducted based on study type, BMI standards, cognitive diagnostic standards, national development level, abdominal obesity diagnostic standards, and follow-up time. Among the subgroups analyzing the correlation between overweight and CI in the elderly, follow-up time ≤ 5 years (OR=0.68, 95%CI 0.58 to 0.80) showed a lower proportion of CI compared to other follow-up periods. In the subgroups analyzing the correlation between obesity and CI in the elderly, follow-up time ≤ 5 years (OR=0.71, 95%CI 0.50 to 1.01) was not statistically significant compared to other follow-up periods. For abdominal obesity, a significant association with increased CI risk in the elderly was found only in the subgroup with a follow-up time of 5-10 years (OR=1.21, 95%CI 1.15 to 1.27), compared with other follow-up periods. ConclusionCurrent evidence suggests that obesity and abdominal obesity may increase the risk of CI in the elderly. Proper weight management is crucial for preventing and delaying the progression of CI in the elderly.