Nutrition knowledge, diet quality and hypertension in a working population.

OBJECTIVE To examine if employees with higher nutrition knowledge have better diet quality and lower prevalence of hypertension. METHOD Cross-sectional baseline data were obtained from the complex workplace dietary intervention trial, the Food Choice at Work Study. Participants included 828 randomly selected employees (18-64 years) recruited from four multinational manufacturing workplaces in Ireland, 2013. A validated questionnaire assessed nutrition knowledge. Food Frequency Questionnaires (FFQ) measured diet quality from which a DASH (Dietary Approaches to Stop Hypertension) score was constructed. Standardised digital blood pressure monitors measured hypertension. RESULTS Nutrition knowledge was positively associated with diet quality after adjustment for age, gender, health status, lifestyle and socio-demographic characteristics. The odds of having a high DASH score (better diet quality) were 6 times higher in the highest nutrition knowledge group compared to the lowest group (OR = 5.8, 95% CI 3.5 to 9.6). Employees in the highest nutrition knowledge group were 60% less likely to be hypertensive compared to the lowest group (OR = 0.4, 95% CI 0.2 to 0.87). However, multivariate analyses were not consistent with a mediation effect of the DASH score on the association between nutrition knowledge and blood pressure. CONCLUSION Higher nutrition knowledge is associated with better diet quality and lower blood pressure but the inter-relationships between these variables are complex.