Dietary assessment of British police force employees: a description of diet record coding procedures and cross-sectional evaluation of dietary energy intake reporting (the airwave health monitoring study)

Abstract

Objectives: Dietary intake is a key aspect of occupational health. To capture the characteristics of dietary behaviour that is affected by occupational environment that may impact on disease risk, collection of prospective multi - day dietary records are required. The aims of this paper are to: i) the collection of multi da y dietary data in the Airwaves health monitoring study, ii) describe the dietary coding procedures applied and ii i ) investigate the plausibility of dietary reporting in this occupational cohort. Design: A dietary coding protocol for this large - scale study was developed to minimise coding error rate. Participants ( n 4,412) who completed 7 - day food records were included for cross - sectional analyses. Energy intake misreporting was estimated using the Goldberg method. Multivariate logistic regression models we re applied to determine participant characteristics associated with energy intake misreporting. Setting: British police force employees enrolled (2007 to 2012) into the Airwave Health Monitoring Study. Results: The mean code error rate per food diary was 3.7% (SD 3.2%). The strongest predictors of energy intake under - reporting were body mass index (BMI) and physical activity. Compared to participants with BMI <25kg/m2, those with BMI >30kg/m2 had increased odds of being classified as under - reporting energ y intake (men OR 5.20 95%CI 3.92, 6.89; women OR 2.66 95%CI 1.85, 3.83). Men and women in the highest physical activity category compared to the lowest were also more likely to be classified as under - reporting (men OR 3.33 95%CI 2.46, 4.50; women OR 4.34 9 5%CI 2.91, 6.55). Conclusions: A reproducible dietary record coding procedure h as been developed to minimise coding error in complex 7 - day diet diaries. The prevalence of energy intake under - reporting is comparable to existing national UK cohort s and, in agreement with previous studies classification of under - reporting was biased towards specific sub groups of participants.