Increasing the relative prices of sugar sweetened beverages (SSBs) and of foods with high-energy but low nutritional density has been proposed as a key strategy to prevent unhealthy weight and related chronic diseases in children. However, evidence on how changes in these prices relate to body mass index (BMI) is mixed, and no study has shown whether there may be changes in risk for chronic disease such as Type 2 diabetes (T2D) or hypertension in youth. We propose to study these relationships using novel price data and clinical records for all children (ages 2-18) in Mexico who received healthcare from IMSS (Instituto Mexicano del Seguro Social; Mexico's largest public healthcare provider) between 2012 and 2016. We do so by exploiting a large adjustment in prices of foods and beverages during this period, driven in part by Mexico's implementation of a tax on SSBs and non-basic, high-calorie foods with more than 275 calories per 100 grams (high-calorie foods, or HCFs henceforth) on January 1, 2014, superposed on variation in food prices due to weather and commodity price shocks. Our proposal has three specific aims:
Aim 1 : Examine if there is a relationship between beverage and food prices and health status of youth. a) Describe how changes in prices of taxed SSBs and HCFs relate to changes in objectively measured BMI, blood pressure and glucose, diagnosed T2D or hypertension, and the number of filled prescriptions over time; using 2012-2016 price, biomarker and prescription data for Mexicans aged 2-18. b) Explore how these relationships vary by children's: ? pre-existing health status (glucose, blood pressure levels, or BMI, all recorded at the first clinic visit), ? age, sex and the interaction of both; and ? local poverty index in 2012; using data from the National Council for the Evaluation of Social Development Policy (CONEVAL) and the 2012 Mexican Nutritional and Health Survey (ENSANUT).
Aim 2 : Strengthen the causal interpretation of associations from Aim (1) by addressing the concern of reverse causality, measurement error, omitted variable bias, spurious correlations, and regression to the mean effect.
Aim 3 : Project changes in health outcomes by sex, age and income over 20 years under alternate price change scenarios, using parameters from Aims (1) and (2).
This project studies how changes in prices of sugar-sweetened beverages (SSBs) and high-energy but low nutritional dense foods, such as fast foods or sweets, relate to changes in obesity, glucose and blood pressure levels, and risk for type 2 diabetes and hypertension in children. We do so by using novel price data and clinical records for all children (ages 2-18) in Mexico who received healthcare from IMSS (Instituto Mexicano del Seguro Social; Mexico's largest public healthcare provider) between 2012 and 2016. To obtan new reference to likely effects that price changes from price-based policies may have on childhood obesity and related chronic diseases, we exploit the large variation in prices of unhealthy processed foods and beverages during this period, driven in part by Mexico's implementation of a tax on SSBs and non-basic, high-calorie foods with more than 275 calories per 100 grams (high-calorie foods, or HCFs) on January 1, 2014, superposed on variation in food prices due to weather and commodity price shocks.
