Association between neck circumference and visceral adiposity index among adults in rural Thailand.

The visceral adiposity index (VAI) is an indicator of visceral fat dysfunction associated with atherosclerotic cardiovascular disease (ASCVD). Neck circumference (NC) is a common anthropometric measure of upper-body fat. This study evaluated the association between NC and VAI in a rural Thai population using data from the Health Outcomes and Risk Factors in Rural Communities in Thailand (HARRIT) study (2017-2022). Elevated VAI was defined as > 2.98, while a large NC was considered ≥ 35 cm in men and ≥ 32 cm in women. Multivariable linear and logistic regression analyses were used to assess the relationship between NC and VAI. The study included 2,160 adults with a mean age of 55.6 years, 65.5% of whom were women. The average NC was 33.6 cm, and 63.4% of participants had a large NC. The mean VAI was 6.3, with 75.5% classified as having an elevated VAI. A large NC was significantly associated with a higher VAI (adjusted β = 2.31, 95% confidence interval [CI]: 1.91-2.71). Participants with a large NC had a 26% higher prevalence of elevated VAI (adjusted prevalence ratio [APR] = 1.26, 95% CI: 1.19-1.33). For individuals under 60, the APR was 1.33 (95% CI: 1.23-1.44); for those aged 60 and above, it was 1.17 (95% CI: 1.09-1.26). In conclusion, NC is positively associated with VAI among rural Thai adults. This highlights the need for further research to explore the relationship between NC and ASCVD outcomes and to establish sex- and age-specific NC cutoffs.