Associations between lifestyle factors and an unhealthy diet

Background: Unhealthy dietary patterns have been associated with other unhealthy lifestyle factors such as smoking and physical inactivity. Whether these associations are similar in high-and low-educated individuals is currently unknown. Methods: We used information of the EPIC-NL cohort, a prospective cohort of 39 393 men and women, aged 20-70 years at recruitment. A lifestyle questionnaire and a validated food frequency questionnaire were administered at recruitment (1993-97). Low adherence to a Mediterranean-style diet was used to determine an unhealthy dietary pattern. Lifestyle-related factors included body mass index, waist circumference, smoking status, physical activity level, dietary supplement use and daily breakfast consumption. Multivariate logistic regression analyses were performed for the total population and by strata of educational level. Results: In total 30% of the study population had an unhealthy dietary pattern: 39% in the lowest educated group and 20% in the highest educated group. Physical inactivity, a large waist circumference, no dietary supplement use and skipping breakfast were associated with an unhealthy dietary pattern in both low and high educated participants. Among low educated participants, current smokers had a greater odds of an unhealthy diet compared with never smokers: OR 1.42 (95% CI: 1.25; 1.61). This association was not observed in the high educated group. Conclusions: Most associations between lifestyle-related factors and unhealthy diet were consistent across educational levels, except for smoking. Only among low educated participants, current smokers reported an unhealthier dietary pattern in comparison to never smokers. These results can be used in the development of targeted health promotion strategies.