Diet quality, food intake and incident adult-onset asthma: a LifeLines Cohort Study

Purpose: Dietary factors have been suggested as drivers of the rising prevalence of adult-onset asthma, 
but evidence is inconclusive, possibly due to the complex interrelation with obesity. We aim to explore 
the relation of diet quality and food intake with incident adult-onset asthma in normal weight and 
overweight adults of the prospective population-based LifeLines Cohort Study.
Methods: Incident adult-onset asthma was defined as self-reported asthma at ±4-year follow-up, in 
adults being free of airway disease at baseline. Diet quality scores and food group intake were assessed 
at baseline. Log binomial regression analyses were used to estimate adjusted relative risks (RR) 
between dietary intake (per portion) and incident adult-onset asthma, in categories of BMI (cut-off: 25 
kg/m2
). 
Results: 477 incident asthma cases (75% female, 62% overweight) and 34,698 controls (60% female, 
53% overweight) were identified. Diet quality – assessed by the LifeLines Diet Score and Mediterranean 
Diet Score – was not associated with incident adult-onset asthma in the two BMI groups. Although the 
dietary intake of several food groups differed between cases and controls, after adjustment for 
confounders only few remained associated with adult-onset asthma, including red and processed meat 
(RR: 0.93 per 15 g intake; 95%CI: 0.86-0.99) in the normal weight group and intake of cheese (RR: 1.09 
per 20 g intake; 95%CI: 1.00-1.17) and vegetables (RR: 1.10 per 50 g intake; 95%CI: 1.00-1.21) in the 
overweight group. 
Conclusion: The results of this study question the role of food as ‘simple’ predictor of adult-onset
asthma and call for a clustered approach, including a range of modifiable lifestyle factors and further 
asthma phenotyping.
Keywords: Adult-onset asthma – Nutrition – Food groups – Obesity – Incidence – Epidemiology