Step-defined physical activity and cardiovascular risk among middle-aged Japanese: the National Health and Nutrition Survey of Japan 2006.

Background: Pedometers are becoming widely accepted for physical activity measurement. To use step data effectively, an index which categorizes steps/day by < 5000, ≥ 5000, ≥ 7500, ≥ 10,000, and ≥ 12,500 steps/day has been previously proposed. However, evidence is insufficient to validate this index compared with health outcomes. This study examined the association of steps/day categories with cardiovascular (CVD) risk.

Methods: Cross-sectional data from the National Health and Nutrition Survey of Japan 2006, including 1166 men and 1453 women aged 40-64 years, were analyzed to calculate odds ratios (OR) for having CVD risk including overweight/obesity, blood pressure, high density lipoprotein cholesterol, hemoglobin A1c, and clustered risk factors by steps/day categories.

Results: Among men, inverse gradient associations between steps/day categories and CVD risk (overweight/obesity, blood pressure, HbA1c, and clustered risk factors) were observed. Among women, those taking ≥ 5000 steps/day had substantially lower risk of overweight/obesity and high blood pressure compared with those taking < 5000 steps/day. However, additional decreases of OR by taking more steps were modest among women.

Conclusions: CVD risk was generally lower with higher steps/day categories. Given the limitations of cross-sectional design, further studies, especially using longitudinal designs, are needed to precisely calibrate the association between steps/day and CVD risk.