Japan's intensive health guidance program has limited effects on cardiovascular risk factors: a regression discontinuity analysis.

OBJECTIVES

It is uncertain whether the effects of health counselling programs differ depending on their intensity. This study compared the effectiveness of intensive health guidance (IHG) and less intensive motivation-enhancing guidance (MEG) on cardiovascular risk factors.

STUDY

DESIGN

A regression discontinuity design (RDD) was applied.

METHODS

In Japan's specific health checkup (SHC) and guidance program, those with a high risk of metabolic syndrome are assigned to IHG or MEG. An RDD was applied using an SHC results database. Four groups were created in which IHG or MEG assignment was solely determined by single cut-off values of the running variables of triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), or haemoglobin A1c (HbA1c) measured during SHC. Outcomes were one year's changes in body mass index (BMI), waist circumference (WCF), systolic and diastolic blood pressure, HDL-C, low-density lipoprotein cholesterol, FBG, and HbA1c.

RESULTS

A total of 541,809 observations among 225,115 people from 2008 to 2017 were analysed. Men assigned to IHG had a significantly but slightly lower BMI and WCF than those assigned to MEG the next year, only when TG or FBG was a running variable. There were no significant differences between IHG and MEG for women's BMI and WCF and other cardiovascular risk factors for both sexes.

CONCLUSION

Since IHG has limited additional effects on cardiovascular risk factors compared with MEG, abolishing IHG may have little negative impact on the general public's health.