The association between adult asthma in the United States and dietary total energy intake: a retrospective cross-sectional analysis from NHANES.

Background: Epidemiological research links asthma progression to dietary nonallergic factors, particularly high-calorie intake. However, evidence supporting the relationship with total dietary calorie consumption remains scarce.

Objective: This study aimed to explore the potential correlation between asthma occurrence and total dietary energy intake.

Methods: A retrospective cross-sectional study of 21,354 US adults collected comprehensive participant data, including demographics, blood parameters, fatty acids, zinc, fiber intake, and asthma outcomes. Statistical analyses included interaction effects analysis, smooth curve fitting, and logistic regression.

Results: Of 21,354 participants, 14.77% self-reported asthma diagnosis. After adjusting for confounders, odds ratios (OR) for asthma decreased with higher energy intake: Q2 (OR = 0.77, 95% CI: 0.69-0.86, p < .001), Q3 (OR = 0.66, 95% CI: 0.59-0.75, p < .001), and Q4 (OR = 0.61, 95% CI: 0.53-0.69, p < .001) compared to Q1 (< 17.73 kcal/kg/day). A non-linear (L-shaped) association between energy intake and asthma was observed (p < .001), with a critical threshold around 24 kcal/kg/day, supported by subgroup and sensitivity analyses.

Conclusion: This study reveals an L-shaped trend between total energy intake and asthma in US adults, with a significant threshold at approximately 24 kcal/kg/day.