Leisure time physical activity and insulin resistance in young obese students with hypertension

Relationships between physical activity and plasma leptin levels in healthy children: the Fleurbaix-Laventie Ville Santé II Study

OBJECTIVE

To study the relationships between physical activity and plasma leptin levels in children from a population-based study, taking into account puberty stages.

DESIGN

Subjects were part of the Fleurbaix-Laventie Ville Santé (FLVS) II Study, a longitudinal study on the determinants of weight gain in children and their parents. At baseline examination, 253 girls and 257 boys aged 8-18 y were examined.

MEASUREMENTS

: Height and weight were measured, adiposity was assessed by the sum of four skinfold thicknesses (SSK). Pubertal stage was assigned according to Tanner. Leisure-time physical activity (LTPA) was assessed by the Modifiable Activity Questionnaire and ambulatory activity by pedometer recording over a week. A fasting blood sample was obtained to determine plasma leptin and insulin levels.

RESULTS

Plasma leptin was higher in girls compared to boys (8.3 (1.6-36.5) ng/ml vs 2.2 (0.1-15.3) ng/ml, P<0.001). Multivariate analyses were performed with leptin as dependent variable, and number of steps by day, Tanner stage, insulin and SSK as independent variables. In girls, leptin was negatively correlated to number of steps/day (P<0.001) and positively to SSK (P<0.001) and insulinemia (P<0.001). In boys, leptin was correlated to insulinemia (P<0.001), SSK (P<0.001), Tanner stage (P<.0001), but not to physical activity.

CONCLUSION

Physical activity is negatively related to leptin levels in girls only and this association is independent of fasting plasma insulin. In children, fasting insulinemia remains associated with leptin levels after taking into account adiposity, physical activity and Tanner stage.

Relation between blood pressure and rhinitis in a Japanese adolescent population

Recent studies have reported an association between systolic blood pressure (BP) and rhinitis. The prevalence of allergic rhinitis is 20% to 30% in Japan. The present cross-sectional study was performed to assess the relation between BP and allergic rhinitis in a sample of 2,292 male adolescent high school students who attended the annual school health examination. Of the 2,292 students (mean age, 16 years), 26.6% were considered to have allergic rhinitis based on their responses to a questionnaire, 25.1% were diagnosed with allergic rhinitis by an otolaryngologist, and 12.6% were consistently diagnosed with allergic rhinitis by both questionnaire and an otolaryngologist. There was no difference in systolic BP between subjects with and without allergic rhinitis. Diastolic BP, however, was higher in subjects without allergic rhinitis than in those with allergic rhinitis as diagnosed by questionnaire alone or by both questionnaire and an otolaryngologist. When the subjects were divided into three BP categories (normal, high normal, and hypertension) according to the criteria in the JSH 2000, the rates of allergic rhinitis were similar in the three BP categories. These findings do not confirm a relation between allergic rhinitis and systolic BP.

Relation between Blood Pressure Control, Body Mass Index, and Intensity of Medical Treatment

A cross-sectional study was performed to assess the rates of blood pressure (BP) control to a systolic goal (< 140 mmHg), to a diastolic goal (< 90 mmHg), and to both in a sample of 226 treated hypertensive patients. We also examined the association between obesity, BP control, intensity of treatment defined as dose score (summed ranks of doses of all antihypertensive drugs taken), and number of drugs. Of the 226 treated patients (mean age, 60 years; 20.4% women), 67.7% were controlled to the systolic goal, 72.1% were controlled to the diastolic goal, and 53.5% were controlled to both. Patients were divided into four groups according to body mass index (BMI): less than 23, A; 23-24.9, B; 25-26.9, C; and 27 or more, D. There were no differences in the rates of BP control to the systolic goal, to the diastolic goal, or to both among the four groups; however, the dose score and number of drugs administered were higher in patients of group D than in those of the other groups. There was a tendency toward a higher intensity of drug treatment in obese patients with either controlled or uncontrolled BP. The dose score and number of drugs correlated positively with BMI. In representative subgroups (n = 62), serum insulin and the homeostasis model assessment value of insulin resistance were higher in the patients in group D than in the other groups. These findings indicate that hypertensive patients managed in a hypertension clinic had satisfactory BP control in 53.5% of cases. A higher intensity of medical treatment is needed to achieve BP control in obese hypertensive patients characterized by insulin resistance.

Obesity hypertension in children: a problem of epidemic proportions

Obesity has become an increasingly important medical problem in children and adolescents. In national surveys from the 1960s to the 1990s, the prevalence of overweight in children grew from 5% to 11%. Outcomes related to childhood obesity include hypertension, type 2 diabetes mellitus, dyslipidemia, left ventricular hypertrophy, nonalcoholic steatohepatitis, obstructive sleep apnea, orthopedic problems, and psychosocial problems. Once considered rare, primary hypertension in children has become increasingly common in association with obesity and other risk factors, including a family history of hypertension and an ethnic predisposition to hypertensive disease. Obese children are at approximately a 3-fold higher risk for hypertension than nonobese children. In addition, the risk of hypertension in children increases across the entire range of body mass index (BMI) values and is not defined by a simple threshold effect. As in adults, a combination of factors including overactivity of the sympathetic nervous system (SNS), insulin resistance, and abnormalities in vascular structure and function may contribute to obesity-related hypertension in children. The benefits of weight loss for blood pressure reduction in children have been demonstrated in both observational and interventional studies. Obesity in childhood should be considered a chronic medical condition that is likely to require long-term management. Ultimately, prevention of obesity and its complications, including hypertension, is the goal.

Weight, physical activity, and smoking as determinants of insulinemia in adolescents

BACKGROUND

It is known that insulinemia is the result of the interaction among several factors, such as weight, body fat pattern distribution, and physical activity as well as ethnicity. There is little information regarding this question among Mexican adolescents. The association among fasting insulin levels, weight, fat distribution, physical activity, and cigarette smoking was studied in Mexican adolescents.

METHODS

Cross-sectional data were collected from 352 Mexican adolescents aged 14-19 years (response rate 41.5%). Fasting insulin levels were measured by microparticle enzyme immunoassay; body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC) were determined using standardized techniques, while physical activity was determined by 7-day Stanford physical activity inventory. Cigarette smoking was defined as number of cigarettes/year.

RESULTS

Increased BMI and waist circumference, low physical activity, younger age, and non-smoking were associated with high insulin levels. Non-smokers had higher fasting insulin levels compared to smokers (57.8 pmol +/- 1.84 vs. 49.7 pmol/L +/- 2.8; p = 0.034). However, adjusted odds ratio (OR) between insulin and smoking status was not significant. Multivariate analysis showed the following: insulin increased 1.06 pmol/L for each unit of change in BMI; increased 1.02 pmol/L for each unit of change in waist circumference; increased 1.16 pmol/L for non-smoking, and decreased 1.07 pmol/L for each 250 kcal/day of energy expenditure.

CONCLUSIONS

Our results support the concept that Mexican adolescents who are overweight have abdominal fat distribution and physical inactivity, and significant hyperinsulinemia. The relationship between smoking and lower insulinemia found in this research warrants further study.

Baseline dietary intake and physical activity of Japanese American men in relation to glucose tolerance at 5-year follow-up

Japanese American men (n = 124), with normal glucose tolerance (NGT, n = 69) or impaired glucose tolerance (IGT, n = 55) at baseline, were studied for effects of baseline dietary intake and physical activity on glucose tolerance at baseline and at 5-year follow-up. At baseline, both NGT and IGT men with positive family history of diabetes (FH) showed high intakes of animal fat and protein, but only the NGT men countered this with high levels of energy expenditure. In the total sample at 5-year follow-up, 2-hour plasma glucose was significantly related to intake of animal fat (AF), partial correlation r = 0.32, P < 0.001, adjusted for total energy intake, age, self-reported health, body mass index, FH, and baseline glucose tolerance category. Energy expenditure (EE) was not related to 5-year 2-hour plasma glucose in the total sample, but displayed a relationship with 5-year 2-hour plasma glucose in those IGT (r = -0.27, P < 0.05), but not in those NGT at baseline, and in those with positive FH (r = -0.33, P < 0.05), but not in those with negative FH. Additionally, AF showed a relationship to 5-year 2-hour plasma glucose only for those in the lowest (r = 0.37, P < 0.05) and middle (r = 0.33, P < 0.05) tertiles, but not in the highest tertile of EE. For baseline IGT men, 5-year 2-hour plasma glucose was related to "high vs. low risk" categories of AF intake and EE, but only in men with a positive FH (AF ≥ 25 vs. < 25 g/day: 180.1 ± 38.6 vs. 143.6 ± 39.7 mg/dl, P = 0.048; EE ≤ 2,000 kcal/week vs. > 2,000 kcal/week, 189.9 ± 39.2 vs. 150.8 ± 37.4 mg/dl, P = 0.028; with risk categories combined, i.e., both high, mixed, both low: 192.0 ± 41.3, 165.4 ± 28.4, 139.4 ± 40.9 mg/dl, P = 0.045, linear trend, P = 0.014). Thus, high AF intake and low EE may have long-range detrimental effects on glucose tolerance, especially for those with IGT and positive FH. © 1996 Wiley-Liss, Inc.