Impact of a national screening programme on obesity and cardiovascular risk factors.

Abstract

The benefits of nationwide screening and tailored health guidance on improving obesity and cardiovascular risk factors is uncertain. The aim of the present study was to investigate the association of the national health screening and tailored health guidance with population health outcomes. A fuzzy regression discontinuity design analysed data of men and women aged 40-74 years who participated in a nationwide health screening programme in Japan from 1 April 2008 to 31 March 2019 and were recorded in the Japanese National Database. Exposure was assignment to the national health guidance of counselling on healthy lifestyle and clinical follow-up for individuals found to have waist circumference ≥85 cm for men ≥90 cm for women with one or more cardiovascular risk factors during annual national health screening. The primary outcomes were changes in obesity status and cardiovascular risk factors 1 year after screening. Of 3 490 112 men and 2 328 929 women, the assignment to the health guidance resulted in small reductions in obesity parameters: waist circumference; men, -0.27 cm [95% confidence interval (CI) -0.29 to -0.26]; women -0.34 (-0.41 to -0.27); body mass index, -0.07 kg/m2 (-0.075 to -0.066); -0.11 kg/m2 (-0.13 to -0.10); weight, -0.21 kg (-0.22 to -0.19); -0.28 kg (-0.32 to -0.24) that attenuated over time. Short-term improvements were also observed in blood pressure, haemoglobin A1c, fasting glucose and triglycerides across both sexes. A nationwide health screening programme was associated with only small, and transient improvements in obesity and cardiovascular risk factors.