Associations between dietary diversity and high sensitive C-reactive protein among Japanese workers: findings of a cross-sectional and longitudinal study.

purposeTo clarify the association between dietary diversity and inflammatory status in Japanese workers.

methodsOf 1,460 men and women aged 20-64 years in 2010 (baseline), those who were followed-up at least once between 2011 and 2018 were included in this study; 1,433 participants and 745 participants were included in the cross-sectional and longitudinal analyses, respectively. Dietary intake was assessed using a food frequency questionnaire at baseline, and the dietary diversity score was determined using the Quantitative Index for Dietary Diversity (QUANTIDD). High-sensitivity C-reactive protein (hs-CRP) was taken to indicate inflammatory status at the baseline and follow-up surveys. In the cross-sectional analysis using baseline data, a generalized linear model was used to calculate adjusted means and 95% confidence intervals (CIs) for hs-CRP according to the QUANTIDD score. In the longitudinal analysis, generalized estimating equations were used to calculate the adjusted mean (95% CI) for hs-CRP in follow-up according to the QUANTIDD score at baseline.

resultsIn the cross-sectional analysis, the hs-CRP concentration in male participants was significantly lower in those who had a high QUANTIDD score (adjusted mean [95% CI]: 0.074 [0.009-0.140] mg/dL in the lower group vs. 0.038 [-0.029-0.105] mg/dL in the higher group, p-value = 0.034). In the longitudinal analysis, the hs-CRP concentration of male participants also tended to be lower in those with higher QUANTIDD scores (p-value = 0.103). In both the cross-sectional and longitudinal analyses in women, there was no significant difference between the lower and higher QUANTIDD score groups.

conclusionThese findings suggest that, in male Japanese workers, higher dietary diversity might be important for maintaining a low inflammatory status.