Differential Associations of Visceral Adiposity with Pulmonary Function Impairment by Sex: Identification of a Male-Specific Risk Threshold.

A potential VAI threshold of approximately 103 was observed in males, beyond which the risk of pulmonary function impairment appeared to increase.

• The nonlinear association was examined using restricted cubic splines within multivariate logistic regression models, with knots placed at the 5th, 25th, 75th, and 95th centiles.
• Bootstrap 95% confidence intervals were generated using 500 replicates to assess robustness of the identified threshold.
• Knot placement sensitivity analyses were performed to assess the robustness of the identified VAI threshold.
• The threshold pattern was identified in males specifically, with the VAI value of approximately 103 serving as the identified inflection point.

In females, a more linear association between VAI and pulmonary function impairment was suggested, rather than a threshold pattern.

• The linear pattern in females suggests that risk of pulmonary function impairment may increase across a wider range of VAI values.
• This contrasts with the threshold pattern observed in males at VAI ≈ 103.
• The authors note this pattern suggests 'early and sustained management of visceral adiposity may be important across a wider range of values' in females.

The formal test for sex differences in the association between VAI and pulmonary function impairment was not statistically significant.

• A formal VAI × sex interaction term was included in a combined model to test for sex differences.
• The VAI × sex interaction term was not statistically significant (P = 0.095).
• The authors concluded that 'the evidence for a differential association by sex was inconclusive.'

The study included 6,749 middle-aged and older participants from the 2015 China Health and Retirement Longitudinal Study (CHARLS).

• The sample comprised 3,374 males and 3,375 females.
• Pulmonary function was assessed by peak expiratory flow (PEF).
• Pulmonary function impairment was defined as PEF <80% of the predicted value.
• The study population was drawn from the 2015 wave of the CHARLS.

Visceral adiposity was assessed using the Visceral Adiposity Index (VAI), which was characterized as a core aspect of nutritional status and a modifiable risk factor.

• VAI was described as 'increasingly recognized as a modifiable risk factor for extra-metabolic diseases.'
• The study characterized VAI as 'a core aspect of nutritional status.'
• The authors framed visceral adiposity as relevant to 'healthy aging' through its impact on pulmonary function.
• The study was described as investigating 'differential associations between the Visceral Adiposity Index (VAI) and impaired pulmonary function in middle-aged and older males and females.'

The authors identified the observed male-specific VAI threshold as a potential reference point for targeted lifestyle or nutritional interventions.

• The authors stated the VAI threshold of approximately 103 in males 'could provide a useful reference for identifying individuals who might benefit most from targeted lifestyle or nutritional interventions.'
• The authors emphasized these are 'preliminary findings' that 'require prospective validation before clinical application.'
• The findings were described as highlighting 'the potential value of considering sex in strategies aimed at reducing visceral adiposity to promote respiratory health.'