Altitude and metabolic syndrome in China: Beneficial effects of healthy diet and physical activity

Background The correlation between altitude and metabol-ic syndrome has not been extensively studied, and the me-diation effects of diet and physical activity remain unclear. We evaluated the cross-sectional correlations between altitude and metabolic syndrome and the possible mediation effects of diet and physical activity in China.Methods We included 89485 participants from the China Multi-Ethnic Cohort. We extracted their altitude information from their residential addresses and determined if they had metabolic syndrome by the presence of three or more of the following components: abdominal obesity, reduced high-den-sity lipoprotein cholesterol (HDL-C), elevated triglycerides, elevated glucose, and high blood pressure at recruitment. We conducted multivariable logistic regression and media-tion analyses for all and separately for Han ethnic participants.Results The participants had a mean age of 51.67 years and 60.56% were female. The risk difference of meta-bolic syndrome was-3.54% (95% confidence interval (CI) =-4.24,-2.86) between middle and low altitudes,-1.53% (95%CI=-2.53,-0.46) between high and low altitudes, and 2.01% (95% CI =0.92, 3.09) between high and middle alti-tudes. Of the total estimated effect between middle and low altitude, the effect mediated by increased physical activity was-0.94% (95% CI =-1.04,-0.86). Compared to low al-titude, the effects mediated by a healthier diet were-0.40% (95% CI =-0.47,-0.32) for middle altitude and-0.72% (95% CI =-0.87,-0.58) for high altitude. Estimates were similar in the Han ethnic group.Conclusions Living at middle and high altitudes was signifi-cantly associated with lower risk of metabolic syndrome com-pared to low altitude, with middle altitude having the lowest risk. We found mediation effects of diet and physical activity.

Automated summary

This study evaluated the correlation between altitude and metabolic syndrome in Chinese residents, as well as the mediation effects of diet and physical activity. The results showed that living at middle and high altitudes was associated with a lower risk of metabolic syndrome compared to low altitude, with middle altitude having the lowest risk. Diet and physical activity played a mediating role in this association.