Television watching and soft drink consumption: associations with obesity in 11- to 13-year-old schoolchildren

OBJECTIVES

To determine the prevalence of obesity among sixth- and seventh-grade students in a school-based setting, and to identify lifestyle parameters associated with obesity.

METHODS

Sixth- and seventh-grade students (n = 385, 186 boys and 199 girls) from 3 schools participated in a school-based screening study, and 319 completed a short questionnaire. Height and weight were measured, and body fat as a percentage of body weight was obtained using a Tanita bioelectrical impedance scale.

RESULTS

Overall, 35.3% of students had a body mass index (BMI; calculated as the weight in kilograms divided by the height in meters squared) at or above the 85th percentile, and half these students (17.4%) had a BMI at or above the 95th percentile. Rates were higher among Latino and lower among Asian than non-Hispanic white students. Significant associations were found between BMI and hours of television watched per evening and daily soft drink consumption. The mean (SE) BMI z score for those watching less than 2 hours per night (0.34 [0.09]) was lower than for those watching 2 or more hours per night (0.82 [0.08]; P<.001). The mean (SE) BMI z score for those consuming less than 3 soft drinks per day (0.51 [0.07]) was lower than for those consuming 3 or more soft drinks per day (1.02 [0.13]; P =.003). Latino students watched more television (2.4 hours per night) than did non-Hispanic white or Asian students (1.3 hours per night; P<.001 for each) and consumed more soft drinks (1.6 per day) than non-Hispanic white students (1.1 per day; P =.004) or Asian students (0.7 per day; P<.001).

CONCLUSIONS

Time spent watching television and the number of soft drinks consumed were significantly associated with obesity. Latinos spent more time watching television and consumed more soft drinks than did non-Hispanic white or Asian students. These findings will be beneficial in developing preventive measures for these children.

The effect of hormone replacement therapy and exercise on cardiovascular disease risk factors in postmenopausal women

Following menopause, women show an increased risk of heart disease to a level equal that of men. This elevated risk is thought to be due, at least partly, to changes in blood lipid and fibrinogen levels. The purpose of this article is to review the published research on the relationship between both exercise and hormone replacement with regards to common cardiovascular disease (CVD) risk factors and the relative importance of each. Menopause is associated with increased total serum cholesterol, triglycerides and fibrinogen, and a decrease in high density lipoprotein (HDL) cholesterol levels. The major reason for these changes following menopause is believed to be a result of fluctuations in hormonal status, primarily a deficiency in estrogen. Intervention may be justified since estrogen replacement therapy has been shown to decrease the risk of developing CVD and to have a significant impact on many of the CVD risk factors. The results vary from study to study, but generally estrogen replacement has been found to decrease total cholesterol and fibrinogen, while increasing HDL cholesterol and triglycerides. All of these changes, other than the increase in triglycerides, are seen as positive. The addition of progestogen to estrogen may negate some of the beneficial changes of estrogen, most notably the increase in HDL cholesterol levels. However, progestogen has also been reported to offset the increase in triglycerides seen with unopposed estrogen replacement. Thus, there are contradictory effects (both positive and negative) of hormone replacement on CVD risk factors in women. Regular aerobic exercise and resulting improvements in cardiorespiratory fitness have consistently been shown as preventive of CVD. This decreased CVD risk is in part because of the impact of exercise on blood lipids and fibrinogen. Increased aerobic exercise is thought to improve the risk profile, mainly through an increase in HDL cholesterol levels and decreases in triglycerides and fibrinogen. Unfortunately, the majority of research supporting the effects of exercise on CVD risk factors has been done on men. Even when research has included women, very few studies have focused on postmenopausal women. However, the research done on postmenopausal women points to a significantly improved CVD risk factor profile with regular cardiorespiratory exercise.

Evaluation of developmentally appropriate programs for adolescent tobacco cessation

Despite introduction of numerous smoking prevention programs in schools, tobacco use has not declined among adolescents. Schools face the dilemma of what to do with students who smoke and are not ready to quit. This study evaluated two programs based on the stages of change model. The educational program, the Tobacco Education Group (TEG), was designed for adolescents not yet thinking about quitting. The cessation program, the Tobacco Awareness Program (TAP), was intended for adolescents who want to quit. Evaluation was completed on 351 students at six public high schools. Compared to a control group of adolescent smokers not assigned to programs, both intervention groups significantly decreased tobacco use. Self-reported use was validated biochemically. Self-efficacy for quitting increased in both programs. Posttest use was predicted by posttest self-efficacy, peer support, and parental support, after controlling for initial use and initial self-efficacy.

Cardiorespiratory fitness and cardiovascular disease risk factors in postmenopausal women

PURPOSE

The purpose of the present study was to determine if individuals with high levels of cardiorespiratory fitness have better levels of the cardiovascular disease (CVD) risk factors of total cholesterol (TC), HDL cholesterol (HDL), total cholesterol/HDL cholesterol ratio (TC/HDL), triglycerides (TG), and fibrinogen (FIB) when compared with those with low fitness, in 283 nonsmoking, postmenopausal women. Second, we examined the relation between fitness and CVD risk after controlling for use of hormones and other possible confounding factors.

METHODS

These analyses were done on a subset of nonsmoking, postmenopausal women in the Aerobics Center Longitudinal Study (ACLS). Records of postmenopausal women who completed a preventive medicine physical examination between 1987 and 1995 were examined. Cardiorespiratory fitness level was determined by total treadmill time to exhaustion on a graded exercise test; CVD risk factors were assessed via blood analysis.

RESULTS

On cross-sectional regression analysis, fitness was significantly associated (P < or = 0.005) with TC (r2 = 0.08), TC/HDL (r2 = 0.12), TG (r2 = 0.09), and FIB (r2 = 0.06), and an increase in HDL (r2 = 0.04). After controlling for hormone status, age, year of testing, and blood glucose, each outcome variable remained significantly associated with cardiorespiratory fitness (P < 0.05). TC/HDL and TG continued to be significantly related to cardiorespiratory fitness after adjusting for body mass index (BMI) as a control variable (P < 0.01). The lack of significance between TC, HDL, and FIB with cardiorespiratory fitness after adjusting for BMI is likely due to the biological relationship between cardiorespiratory fitness and BMI (r2 = 0.19).

CONCLUSIONS

We conclude that cardiorespiratory fitness is an important independent determinant of blood lipid and FIB levels in nonsmoking postmenopausal women, with or without HRT.

Effect of external beam radiation therapy on serum prostate-specific antigen

The effect of external beam radiation on serum prostate-specific antigen (PSA) was determined in 20 patients with nonmetastatic carcinoma of the prostate. An abnormal PSA was measured in 91 percent and 93 percent, respectively, of the samples collected prior to or during radiation therapy. By seven months, 8/15 men still had an abnormal PSA level. Four of 5 men with an elevated PSA at least twenty-three months after radiation therapy had a positive prostatic biopsy, and 3/3 patients with a normal PSA had a negative ultrasonically guided biopsy. The rate of decline of serum PSA after radiation therapy is variable. These preliminary data suggest that serum PSA may be useful for assessing the local response of prostate cancer to radiation therapy.