Habitual sugar intake and cognitive function among middle-aged and older Puerto Ricans without diabetes

Abstract

Intake of added sugars, mainly fructose and sucrose, has been associated with risk factors for cognitive impairment, such as obesity, the metabolic syndrome and type 2 diabetes. The objective of this analysis was to examine whether habitual intakes of total sugars, added sugars, sugar-sweetened beverages or sweetened solid foods are associated with cognitive function. The present study included 737 participants without diabetes, aged 45-75 years, from the Boston Puerto Rican Health Study, 2004-9. Cognitive function was measured with a battery of seven tests: Mini-Mental State Examination (MMSE), word list learning, digit span, clock drawing, figure copying, and Stroop and verbal fluency tests. Usual dietary intake was assessed with a validated FFQ. Greater intakes of total sugars, added sugars and sugar-sweetened beverages, but not of sugar-sweetened solid foods, were significantly associated with lower MMSE score, after adjusting for covariates. Adjusted OR for cognitive impairment (MMSE score < 24) were 2.23 (95 % CI 1.24, 3.99) for total sugars and 2.28 (95 % CI 1.26, 4.14) for added sugars, comparing the highest with lowest intake quintiles. Greater intake of total sugars was also significantly associated with lower word list learning score. In conclusion, higher sugar intake appears to be associated with lower cognitive function, but longitudinal studies are needed to clarify the direction of causality.

Conflict of interest statement

None of the authors had any conflicts of interest.

Figures

Fig. 1

Multivariate-adjusted OR and 95% CI for cognitive impairment according to quintile of energy-adjusted total sugar (P for trend=0·015) (a), added sugar intakes (P for trend=0·040) (b) and fructose intake (natural plus added) (P for trend=0·072) (c) among participants without diabetes from the Boston Puerto Rican Health Study, 2004–9. OR and 95% CI were plotted against the median of sugar intake of each quintile. The median (range) of total sugar intake (g/d) across quintiles of total sugar intake were: 66·7 (<820), 91·2 (82·0–100·8), 110·0 (100·9–118·3), 130·4 (118·4–145·5) and 168·3 (> 145·5), respectively. The median (range) of added sugar intake (g/d) across quintiles of added sugar intake were: 27·9 (<37·9), 45·8 (38·0–51·0), 57·4 (51·1–64·6), 73·0 (64·7–85·1) and 106·0 (>85·1), respectively. The median (range) of fructose intake (g/d) across quintiles of fructose intake were: 9·6 (<14·2), 17·2 (14·2–19·3), 21·5 (19·4–24·9), 27·9 (25·0–33·8) and 43·7 (>33·8), respectively. Cognitive impairment was defined as a Mini-Mental State Examination score <24. OR was calculated with logistic regression, after adjustment for age (years), sex, educational attainment (< 5th grade, 5th–8th grade, 9th–12th grade, college, or graduate school), poverty (yes or no), acculturation score, smoking (never, former, or current), alcohol use (never, former, or current), physical activity score, BMI (kg/m2; < 25, 25–29·9, or ≥ 30), and the presence of hypertension.