The trajectories of free sugar intake during childhood, their main sources and its association with socio-economic factors: generation XXI birth cohort

The study aimed to describe trajectories of free sugar (FS) intake, its main sources and the associations with socio-economic status (SES) in Portuguese children/adolescents evaluated at 4, 7, 10 and 13 years of age from Generation XXI birth-cohort. Dietary intake was assessed through 3-day food diaries (<i>n</i> 5268). Added sugar intake was estimated following a systematic methodology, and FS was based on the WHO definition. A mixed-effects model with linear and quadratic terms for time was used to estimate FS trajectories and its association with SES, adjusting for children's sex, age, BMI and SES. The FS mean intake (g/day) was 37, 47, 51 and 48 at 4, 7, 10 and 13 years, respectively. FS intake increased 4·6 g/year (CI 95 %: 4·20, 5·04), but velocity decreased by 0·3 g/year² until 13 years. At all ages, the main food source was sweets. Some item's consumption declined (sweets 25-21 % and yoghurts 22-7 %) as children grew older. Inversely, soft drink intake increased (9-18 %). Boys and children from younger mothers had higher FS intake, whereas higher maternal-SES was associated with lower children's FS intake: occupational status (<i>β</i> = -3·5; 95 % CI: -4·97, -1·94), years of education (<i>β</i> = -3·7; 95 % CI: -4·93, -2·40) and household income (<i>β</i> = -4·9; 95 % CI: -6·50, -3·27). The FS trajectories were similar by SES categories but different by obesity status (interaction term <i>β</i> = -1·04; CI 95 % (-1·50, -0·59)). An increasing FS trajectory during childhood is mainly driven by an increasing intake of soft drinks and nectars. The FS trajectory pattern did not change according to SES categories, but children's FS intake was always higher when their mothers had a lower SES.