[A nested case-control study on the relationship between occupational physical activity, heredity factors and...

To examine the associations between occupational physical activity, heredity factors and metabolic syndrome (MS) in a Chinese population.

Based on the MS cohort study in Jiangsu province, subjects were followed-up, and blood samples were collected at the same time for biochemical indicators measurement. Newly confirmed MS patients according to US. National Cholesterol Education Program Adult Treatment Guidelines III (NCEP-ATPIII) were recruited as cases. Controls were 1:1 matched with cases by region, gender and age (+/- 2 years). In total, 389 MS patients and 389 controls were recruited as study subjects. Nested case-control study was applied for the present analysis. TaqMan fluorescence probe method was used to detect the genetic polymorphism of PPARalpha intron 1A/C(rs135539).

(1) Compared to low physical activity group, the subjects with heavy physical activity were positively associated with MS (OR = 2.18, 95%CI: 1.08 - 4.38). (2) The subjects, with a family history of hypertension (OR = 1.44, 95%CI: 1.02 - 2.03) or type 2 diabetes (OR = 3.25, 95CI: 1.28 - 8.20), were significantly increased the occurrence of MS. (3) The genotype (AA, AC, CC) of PPARalpha intron 1A/C was not found to be related to MS. The OR of AC and CC genotype (compared to the genotype AA) were 0.98 (95%CI: 0.70 - 1.36) and 0.75 (95%CI: 0.44 - 1.29), respectively. (4) Effect modifications were observed between family history of hypertension and moderate physical activity (OR = 2.47, 95%CI: 1.00 - 6.06) or heavy physical activity (OR = 3.82, 95%CI: 1.31 - 11.15) on the development of MS.

Heavy physical activity, with family history of hypertension or type 2 diabetes, seemed to be positively correlated with the risk of MS. Effect modifications were observed between occupational physical activity and family history of hypertension which might be associated with an increased risk of MS.