Impact of Physical Activity Frequency, Duration, and Intensity on Senile Cataract Risk: A Mendelian Randomization Study

Abstract

Purpose: We aimed to determine the causal effects of physical activities with different frequencies, durations, and intensities on the risk of senile cataracts using Mendelian randomization (MR).

Methods: A bidirectional two-sample MR approach was used to determine the association between physical activity and senile cataract risk. Our primary analysis used the inverse variance weighted method, and secondary analyses included MR-Egger regression, MR-PRESSO, and Cochran's Q statistic to evaluate heterogeneity and pleiotropy. Causal estimates were presented as odds ratios (ORs) with 95% confidence intervals (95% CIs).

Results: Genetically predicted moderate physical activity ≥ 10 min/wk (OR = 0.765, 95% CI = 0.627-0.936, P = 8.73E-03), vigorous physical activity ≥ 10 min/wk (OR = 0.691, 95% CI = 0.521-0.917, P = 1.04E-02), moderate-to-vigorous physical activity levels (OR = 0.552, 95% CI = 0.369-0.823, P = 3.75E-03), and overall acceleration average (OR = 0.952, 95% CI = 0.926-0.978, P = 3.80E-04) were associated with a decreased risk of senile cataract while walking ≥ 10 min/wk (OR = 0.972, 95% CI = 0.741-1.275, P = 8.36E-01) had no significant correlation. The reverse MR analysis showed no reversal causality from senile cataract to physical activity except for walking ≥ 10 min/wk (OR = 0.951, 95% CI = 0.923-0.979, P = 7.30E-04).

Conclusions: Our findings suggest that moderate to vigorous physical activity with higher frequency and longer duration will causally reduce the risk of senile cataracts, and there is no reverse causal relationship.

Translational relevance: These findings underscore the potential of incorporating physical activity into preventive health strategies for senile cataracts.

Figure 1.

Design flow chart for the Mendelian randomization study. SNP, single nucleotide polymorphism; WM, weighted median; MR, Mendelian randomization; IV, instrumental variable.

Figure 2.

MR estimates, heterogeneity, and pleiotropy analysis for the causal effect of physical activity on senile cataract. MR, Mendelian randomization; OR, odds ratio; CI, confidence interval; IVW, inverse variance weighted, Walking ≥ 10 min/wk: number of days per week walked for 10 or more minutes; MPA ≥ 10 min/wk, number of days per week of moderate physical activity for 10 or more minutes; VPA ≥ 10 min/wk, number of days per week of vigorous physical activity for 10 or more minutes; MVPA, moderate-to-vigorous physical activity levels; OAA, overall acceleration average.

Figure 3.

MR estimates, heterogeneity, and pleiotropy analysis for the causal effect of senile cataract on physical activity. MR, Mendelian randomization; OR, odds ratio; CI, confidence interval; IVW, inverse variance weighted; Walking ≥ 10 min/wk, number of days per week walked for 10 or more minutes; MPA ≥ 10 min/wk, number of days per week of moderate physical activity for 10 or more minutes; VPA ≥ 10 min/wk, number of days per week of vigorous physical activity for 10 or more minutes; MVPA, moderate-to-vigorous physical activity levels; OAA, overall acceleration average.