Impact of school district sugar-sweetened beverage policies on student beverage exposure and consumption in middle schools.

PURPOSE: To determine the associations between 1) exposure to sugar-sweetened beverages (SSB) in middle schools and student consumption of SSB during the school day; and 2) school district policies about SSB and exposure to SSB in schools. METHODS: The strength of school district SSB policies was scored on three SSB policy indicators. Student SSB consumption at school was assessed by a self-administered Beverage and Snack Questionnaire. Exposure to SSB at school was defined as the number of vending slots and SSB venues as determined on-site at each school. Multivariate analysis considered the multilevel nature of the data. RESULTS: Data from 9151 students in 64 middle schools in 28 districts were used in the analysis. With schools as the unit of analysis, the proportion of students who consumed any SSB at school ranged from 19.2% to 79.8%. SSB exposure was a significant predictor of SSB consumption (beta=.157, p < .001). SSB consumption was not significantly associated with the size of the school, the racial or ethnic composition of the school's students, or the proportion of students eligible for free and reduced price meals. District SSB policy scores ranged from 0 to 6 with a mean score of 3.25 (+/-2.15). District SSB policy was a significant predictor of SSB exposure (beta=-9.50, p < .0002). CONCLUSIONS: School district SSB policies and exposure to SSB in middle schools are associated with student SSB consumption. Interventions to improve policies and their implementation may offer opportunities to improve the diets of adolescents.

A comprehensive coding system to measure the quality of school wellness policies.

In 2006, all local education agencies in the United States participating in the National School Lunch Program were required to establish school wellness policies that covered nutrition education, nutrition standards for school foods, and physical activity. The purpose of this psychometric study was to develop and evaluate the properties of a comprehensive and quantitative coding system to evaluate the quality of these policies. A 96-item coding tool was developed to evaluate seven goal areas: nutrition education, standards for US Department of Agriculture child nutrition programs and school meals, nutrition standards for competitive and other foods and beverages, physical education, physical activity, communication and promotion, and evaluation. Each goal area subscale and the total scale were scored on two dimensions: comprehensiveness and strength. Reliability was assessed by having pairs of researchers from four different states code a sample of 60 polices between July 2007 and July 2008. Goal area subscales were internally reliable (Cronbach's alpha=.60 to .93). Adequate interrater reliability scores were obtained at each level of scoring: total comprehensiveness and strength scores (intraclass correlation coefficient 0.82), subscale scores (intraclass correlation coefficient 0.70), and individual items (intraclass correlation coefficient 0.72). This coding system provided a reliable method for analyzing and comparing school district wellness policies in single or multistate studies.

Freezing cycles enhance winter injury in Picea rubens.

We examined changes in chlorophyll absorbency in red spruce (Picea rubens Sarg.) foliage in response to simulated freezing cycles. Current-year branch tips were collected from 16 trees on January 8, January 20, February 8 and February 26, 1996. Tissue was subjected to freezing cycle treatments with a minimum of -35 degrees C and a maximum of 3 degrees C for a one-cycle treatment, and -9, -6, -3, 0 or 3 degrees C for four-cycle treatments. Samples were frozen at a rate of 5 degrees C h(-1), and warmed at 12 to 15 degrees C h(-1). Controls were held at -9 degrees C. Temperatures during the three-day periods preceding each sample date averaged -18, 4.7, -9.6 and 3.7 degrees C, respectively. On January 8, treated trees showed no significant (P > 0.1) increase in the breakdown of chlorophyll, as measured by the ratio of chlorophyll a absorbency (435 nm) to phaeophytin a absorbency (415 nm), compared with control branch tips. On later sampling dates, seven trees consistently exhibited needle reddening and nine exhibited few symptoms (< 10% of total needle surface reddened) after four-cycle treatments. On February 26, chlorophyll degradation in trees with needle reddening differed (P < 0.05) from the control by 26, 26, 16, 14 and 15% for the 3, 0, -3, -6 and -9 degrees C maxima, respectively. No detectable chlorophyll degradation occurred after a one-cycle treatment in any trees on any sampling date. Freezing cycles with sub-zero maxima and a -35 degrees C minimum enhanced winter injury in red spruce after a midwinter thaw had rendered the trees susceptible to freezing damage.