Associations between dietary intake and asthma outcomes: Evidence from pooled analysis in two independent multiethnic...

Asthma is a chronic respiratory condition that poses significant public health challenges worldwide, including Singapore.

Associations between dietary intake and asthma outcomes were assessed in two independent cohorts: the Singapore/Malaysia Cross-Sectional Genetics Epidemiology Study (SMCGES; n = 12,172) and the Singapore Multi-Ethnic Cohort Phase 2 follow-up (MEC2_T2; n = 12,353).

Dietary intake was assessed using a 16-food-group food frequency questionnaire (FFQ) in SMCGES, and a validated 163-item population-specific FFQ in MEC2_T2. Asthma status was determined through self-reported physician diagnosis, with recent asthma attacks and inhaler requirements analyzed as clinically relevant phenotypes. Multivariable logistic regression models adjusted for demographic and lifestyle factors were applied with Bonferroni correction, and meta-analyses across 16 food groups were conducted to derive pooled effect estimates and assess between-cohort heterogeneity.

Asthma prevalence was 19.7% in SMCGES and 9.83% in MEC2_T2. Among patients with asthma, 18.8% (SMCGES) and 18.7% (MEC2_T2) experienced recent asthma attacks, while inhaler requirement was lower in SMCGES (5.9%) than MEC2_T2 (18.4%). Fruit (pooled odds ratio [pOR] = 0.65; 95% confidence interval [CI], 0.57-0.74; P < .001) and nuts (pOR = 0.90; 95% CI, 0.85-0.95; P < .001) intake lowered the odds of asthma, while seafood intake increased the associated odds (pOR = 1.13; 95% CI, 1.07-1.20; P < .001). Fruit intake showed moderate heterogeneity (I ² = 63%; P = .10), with no heterogeneity for nuts (I ² = 0; P = .69) or seafood (I ² = 0, P = .56).

Pooled findings across two independent cohorts highlight specific food groups that may influence asthma outcomes.