Evaluating the "2cm2kg" Target in Japan's Specific Health Checkups: Evidence From the Panasonic Cohort Study 30

The national Specific Health Checkups and Guidance program set a "2 cm waist circumference (WC) and 2 kg body weight (BW) reduction" (2cm2kg) target in Japan. This study aimed to examine the validity of the 2cm2kg target.

We analyzed data from the Panasonic cohort study of adults ≥ 40 years undergoing health checkups in 2020. Anthropometrics, glucose, blood pressure (BP), lipids, and liver function were measured at baseline and 1 year. Achievement of 2cm2kg was defined as ≥ 2 cm WC and ≥ 2 kg BW reductions. Analyses included covariance, logistic regression, spline, and receiver operating characteristic analyses.

Among 30,240 participants, the aim of 2cm2kg achieved reductions of over 5 cm in WC and 5 kg in BW. This was significantly associated with improvements in multiple metabolic indicators-including triglycerides, low-density lipoprotein cholesterol, BP, liver function, and high-density lipoprotein cholesterol (all p < 0.0001). Greater reductions in WC and BW yielded larger, consistent benefits across subgroups by sex, age ≥ 50, and baseline medication use. Cutoff values predicting metabolic improvements were generally -1 to -2 cm WC and -1 to -2 kg BW, and spline analyses showed monotonic improvements with greater WC and BW reductions.

Reductions ≥ 2cm2kg were associated with metabolic improvements in Specific Health Checkups and Guidance-eligible individuals.