Association of Mediterranean diet and cardiorespiratory fitness with the development of pre-diabetes and diabetes: the Coronary Artery Risk Development in Young Adults (CARDIA) study

Objective To better understand the association between a modified Mediterranean diet pattern in young adulthood, cardiorespiratory fitness in young adulthood, and the odds of developing pre-diabetes or diabetes by middle age. Research design and methods Participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study who did not have pre-diabetes or diabetes at baseline (year 0 (Y0), ages 18–30) and who had data available at the Y0 and year 25 (Y25) visits were included in this analysis (n=3358). Polytomous logistic regression models were used to assess the association between baseline dietary intake and fitness data and odds of pre-diabetes or diabetes by middle age (Y25, ages 43–55). Results At the Y25 visit, 1319 participants (39%) had pre-diabetes and 393 (12%) had diabetes. Higher baseline fitness was associated with lower odds of pre-diabetes and of diabetes at Y25. After adjustment for covariates, each SD increment in treadmill duration (181 s) was associated with lower odds for pre-diabetes (OR 0.85, 95% CI 0.75 to 0.95, p=0.005) and for diabetes (OR 0.71, 95% CI 0.60 to 0.85, p=0.0002) when compared to normal glycemia. A modified Mediterranean diet pattern was not associated with either pre-diabetes or diabetes. No interaction between cardiorespiratory fitness and dietary intake was observed, but baseline fitness remained independently associated with incident pre-diabetes and diabetes following adjustment for diet. Conclusions Higher cardiorespiratory fitness in young adulthood, but not a modified Mediterranean diet pattern, is associated with lower odds of pre-diabetes and of diabetes in middle age. Trial registration number NCT00005130