Unique Nationwide Screening Program Fails to Move the Needle on CVD Risk Factors

Japan's mass screening and counseling intervention resulted in only modest population-wide improvements in obesity and cardiovascular disease (CVD) risk factors, a study showed.

Among over 3.4 million men and 2.3 million women, those who met the threshold for high waist circumference with high blood pressure, impaired glucose tolerance, or dyslipidemia and received lifestyle guidance and counseling saw few 1-year reductions across obesity parameters (e.g., men's waist circumference down by 0.11 inches and BMI reduced by 0.07), which diminished over 4 years of follow-up, reported Taizo Motonishi, PhD, of Kansai University in Suita, Japan, and colleagues.

Short-term improvements in blood pressure, HbA1c, glucose, and triglyceride levels were also lost within a few years, they noted in the European Journal of Preventive Cardiology.

These mixed findings do not justify a randomized trial for such a large-scale, expensive screening intervention, Motonishi and team said.

Receipt of health guidance in the Japanese intervention was associated with lifestyle changes including reduced smoking and more exercise among men, and less snacking in women. "Population-level strategies dealing with specific risk factors including physical activity can be effective, but they need to be sustained over time," the researchers argued.

Deepak Bhatt, MD, MPH, of the Icahn School of Medicine at Mount Sinai Health System in New York City, agreed that the challenge is "maintaining improvements in weight and other risk factors over the long term."

"This study shows that prevention isn't easy. It takes a lot of work to make modest changes in cardiovascular risk factors such as obesity. But even small changes, such as those seen in this study, might still have value when applied to a large number of people at a national level," he told MedPage Today.

However, Bhatt said, it is debatable whether it would be cost-effective to implement similar national programs in countries like the U.S.

Japan is unique for having an annual nationwide health screening program -- in a large general population with universal health insurance coverage -- aimed at connecting unaware at-risk individuals to medical and preventive actions before they become high risk.

This program is still ongoing, co-author Yoko Nakao, MD, PhD, a cardiologist and cardiovascular epidemiologist at the University of Leeds in England, told MedPage Today.

The researchers contrasted Japan's preventive approach with that of Europe, where systematic screening is recommended only in individuals with any cardiovascular risk and is considered in the general population (in men over 40 and women over 50) every 5 years.

Notably, Denmark's experiment with more intensive population-based screening for subclinical CVD -- comprising electrocardiography-gated CT and ankle-brachial blood-pressure measurements -- did not prevent deaths in men, except possibly in those younger than 70 in the DANCAVAS trial reported this summer.

A more targeted approach to this screening intervention is under investigation in the ongoing DANCAVAS II study.

"Whether comprehensive CVD screening is useful for women or people with various socioeconomic status remains to be seen," Nakao said, cautioning that this type of screening may show different results between a randomized trial and real-world practice.

For the present study, the authors used records from the Japanese National Database on 30 million men and women ages 40 to 74 who had participated in the national screening program from 2008 (when it was first implemented) to 2018.

Lifestyle guidance consisted of an initial session with a clinician, followed by support lasting at least 3 months, which may be renewed annually for people who continue to be flagged for obesity.

Observational data were subject to regression discontinuity analysis, in which health outcomes were compared between groups just above and just below the threshold for assignment to health guidance: waist circumference ≥85 cm (33.5 in) for men and ≥90 cm (35.4 in) for women, in addition to one or more cardiovascular risk factors.

This study design emulates randomization and mitigates the unmeasured confounding of observational studies, Nakao explained.

Motonishi and team acknowledged that their analysis was still limited by the ethnically homogenous study population and the non-participation of eligible citizens.

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