The impact of a supermarket nutrition rating system on purchases of nutritious and less nutritious foods.

OBJECTIVE: The current study examines the impact of a nutrition rating system on consumers' food purchases in supermarkets. DESIGN: Aggregate sales data for 102 categories of food (over 60 000 brands) on a weekly basis for 2005-2007 from a supermarket chain of over 150 stores are analysed. Change in weekly sales of nutritious and less nutritious foods, after the introduction of a nutrition rating system on store shelves, is calculated, controlling for seasonality and time trends in sales. SETTING: One hundred and sixty-eight supermarket stores in the north-east USA, from January 2005 to December 2007. SUBJECTS: Consumers purchasing goods at the supermarket chain during the study period. RESULTS: After the introduction of the nutrition ratings, overall weekly food sales declined by an average of 3637 units per category (95 % CI -5961, -1313; P<0·01). Sales of less nutritious foods fell by 8·31 % (95 % CI -13·50, -2·80 %; P=0·004), while sales of nutritious foods did not change significantly (P=0·21); as a result, the percentage of food purchases rated as nutritious rose by 1·39 % (95 % CI 0·58, 2·20 %; P<0·01). The decrease in sales of less nutritious foods was greatest in the categories of canned meat and fish, soda pop, bakery and canned vegetables. CONCLUSIONS: The introduction of the nutrition ratings led shoppers to buy a more nutritious mix of products. Interestingly, it did so by reducing purchases of less nutritious foods rather than by increasing purchases of nutritious foods. In evaluating nutrition information systems, researchers should focus on the entire market basket, not just sales of nutritious foods.

Predicting complications after bariatric surgery using obesity-related co-morbidities.

BACKGROUND: To determine which (if any) pre-surgery obesity-related co-morbidities predict complications after bariatric surgery. METHODS: Claims data are analyzed for 1,760 patients aged 18-62 who were covered by one of seven New York State health plans and underwent bariatric surgery during 2002-2005. Data covered 6 months before to 18 months after surgery. Pre-surgery obesity-related comorbidities studied include: diabetes, hyperlipidemia, hypertension, asthma, arthritis, sleep apnea, GERD, and depression. Specific post-surgery complications examined are: stenosis, complications associated with the anastomosis, dumping syndrome, and sepsis. RESULTS: Obesity-related co-morbidities prior to surgery are significantly correlated with the probability of developing complications up to 180 days after bariatric surgery. For example, sepsis was significantly more likely in patients who had diabetes, arthritis, or sleep apnea prior to surgery. An additional pre-surgery comorbidity is associated with a 27.5% higher likelihood of dumping syndrome, 24.5% higher likelihood of complications associated with the anastomosis, and 23.5% higher probability of sepsis in the first 180 days after surgery. Among the individual co-morbidities studied, sleep apnea and GERD are most predictive of complications. CONCLUSION: Patients who exhibit multiple obesity-related co-morbidities prior to bariatric surgery are at significantly elevated risk of post-surgery complications and merit closer monitoring by health care professionals after bariatric surgery. Limitations of this study include nonexperimental data and an unknown degree of under-reporting of pre-surgery co-morbidities in claims data.