Mexican households' food shopping patterns in 2015: analysis following nonessential food and sugary beverage taxes.

OBJECTIVE: To examine patterns of taxed and untaxed food and beverage shopping across store types after Mexico's sugary drink and non-essential food taxes, the nutritional quality of these patterns and the socio-economic characteristics associated with them. DESIGN: We performed k-means cluster analyses using households' percentage of food and beverage purchases from each store type (i.e. convenience stores, traditional shops (e.g. bodegas, tiendas, mom-and-pop shops), supermarkets, wholesalers and others). We calculated adjusted mean proportions of taxed and untaxed products (ml or g/capita per d) purchased in each pattern. We studied the associations between households' SES and shopping patterns using multinomial logistic regressions. Within shopping patterns, we obtained mean volumes and proportions of taxed and untaxed food and beverage subgroups and calculated the proportion of products purchased at each store type. SETTING: Mexico. PARTICIPANTS: Urban Mexican households (n 5493) from the Nielsen Mexico Consumer Panel Survey 2015. RESULTS: We found four beverage shopping patterns and three food shopping patterns, driven by the store type where most purchases were made. For beverages, 48 % of households were clustered in the Traditional pattern and purchased the highest proportion of taxed beverages. Low-SES households had the highest probability of clustering in the Traditional beverage shopping pattern. For foods, 35 % of households were clustered into the Supermarket pattern. High-SES households had the highest probability of clustering in the Supermarket food shopping pattern. CONCLUSIONS: The combination of store types where Mexican households purchase packaged foods and beverages varies. However, households in all shopping patterns and SES purchase taxed beverages mainly at traditional stores. Store-level strategies should be developed to intervene on traditional stores to improve the healthfulness of purchases.

The caloric and sugar content of beverages purchased at different store-types changed after the sugary drinks taxation in Mexico.

BACKGROUND: Following the 2014 sugary drinks tax implementation in Mexico, promising reduction in the volume of purchases of taxed beverages were observed overall and at different store-types. However, the tax's effects on purchasing patterns of calories and sugar remain unclear. METHODS: Using longitudinal data from Mexican households (n = 7038), we examined changes in volume, calories and total sugar of packaged beverages purchased from 2012 to 2016 overall and by store-type. We used fixed effects models to estimate means for volume, calories, and sugar of households. To address the potential selectivity from households shopping at different stores, we calculated inverse probability weights to model the purchases changes over time by store-type. RESULTS: For taxed beverages, the volume of purchases declined by - 49 ml and -30 ml in the first year and second year post tax (2014 and 2015, respectively), while purchases leveled off in the third year of the tax (2016). Calories and sugar from taxed beverage purchases decreased over time, with the majority of the declines occurring in the first two years post-tax implementation. The volume of untaxed beverage purchases increased, whereas changes in calories and total sugar of untaxed beverages were minimal. Store level purchases of taxed beverages significantly decreased in the first two years post taxation (2014 and to 2015) only in supermarkets and traditional stores. The steepest declines in purchases of taxed beverages in 2014 were observed at supermarkets (- 40 ml or - 45%). The volume of purchases of untaxed beverages increased over time in almost all store-types, while calories and sugar minimally decreased over time. CONCLUSION: Although the Mexican tax on SSBs has lowered the purchases of sugary drinks 3 years after the tax implementation, the tax should be strengthened and store-specific interventions should be implemented to further reduce SSBs purchases in the Mexican population.

Sleep duration and obesity among adolescents transitioning to adulthood: do results differ by sex?

OBJECTIVES: To examine the association between short sleep duration and obesity among adolescents (mean age 16 years) transitioning into young adulthood (mean age 21 years) in the National Longitudinal Study of Adolescent Health (N = 10,076). STUDY DESIGN: Self-reported sleep duration was categorized as <6, 6-8, or >8 hours. Obesity status, using measured height and weight, was defined as body mass index ≥95th percentile in adolescence and body mass index ≥30 kg/m(2) in young adulthood. RESULTS: Cross-sectionally, short sleep duration was associated with obesity in adolescent males (prevalence ratio 1.8 [95% CI, 1.3-2.4]) but not in females (prevalence ratio 1.0 [95% CI, 0.7-1.4]). In longitudinal analyses, short sleep duration in adolescence was associated with incident obesity in both males and females (risk ratio 1.2 [95% CI, 1.0-1.6]) in young adulthood. No interactions by sex were noted. CONCLUSIONS: Analyzing the association of sleep duration and obesity longitudinally resolved sex discrepancies observed in earlier cross-sectional analyses. Optimizing sleep duration during adolescence may be an effective intervention to prevent excess weight gain in young adults.