Higher Global Diet Quality Score Is Associated with Less 4-Year Weight Gain in US Women.

backgroundWe have developed a simple and globally applicable tool, the Global Diet Quality Score (GDQS), to measure diet quality.

objectivesTo test the utility of the GDQS, we examined the associations of the GDQS with weight change and risk of obesity in US women.

methodsHealth, lifestyle, and diet information were collected from women (n = 68,336) in the Nurses' Health Study II (aged 27-44 y in 1991) through repeated questionnaires (1991-2015). The GDQS has 25 food groups (maximum = 49 points) and scoring higher points reflects a healthier diet. The association between GDQS change in 4-y intervals and concurrent weight change was computed with linear models adjusted for confounders.

resultsMean ± SD weight gain across 4-y periods was 1.68 ± 6.26 kg. A >5-point improvement in GDQS was associated with -1.13 kg (95% CI: -1.19, -0.77 kg) weight gain compared with a score change of <±2 points. For each 5-point increase, weight gain was 0.83 kg less for age <50 y compared with 0.71 kg less for age ≥50 y (P-interaction < 0.05). A >5-point score decrease was associated with 1.13 kg (95% CI: 1.04, 1.22 kg) more weight gain in women aged <50 y and 0.81 kg more (95% CI: 0.63, 0.98 kg) in women aged ≥50 y. Compared with little change in score, obesity RR was 0.77 (95% CI: 0.74, 0.81) for a >5-point increase and 1.32 (95% CI: 1.26, 1.37) for a >5-point decrease. Risk of obesity did not differ by age. Compared with other diet quality scores, the Alternate Healthy Eating Index-2010 had somewhat stronger associations than the GDQS (P < 0.05) but the GDQS had stronger associations than the Minimum Dietary Diversity for Women score (P < 0.05).

conclusionsImprovement of diet quality as measured by the GDQS was associated with less weight gain and risk of obesity in US women. The association was stronger for women aged <50 y. Associations similar in direction and magnitude were observed between the GDQS and obesity across age groups.