Long-term morbidity and mortality of overweight adolescents. A follow-up of the Harvard Growth Study of 1922 to 1935

Randomized crossover study of 40% vs. 55% carbohydrate weight loss strategies in women with previous gestational diabetes mellitus and non-diabetic women of 130-200% ideal body weight

OBJECTIVE

The optimum diet composition for weight loss in obese women with or without previous gestational diabetes mellitus remains to be determined. Weight loss may be especially important for the latter group in terms of preventing future gestational as well as non-insulin dependent diabetes mellitus. We studied 40% vs. 55% carbohydrate calorically restricted diets to compare weight loss and metabolic response.

METHODS

We performed a prospective, 12-week, blinded, randomized crossover study of 25 obese women; 13 of whom had previous gestational diabetes. Each woman was allocated to a treatment regimen for 6 weeks and then "crossed over" to the alternative regimen for an additional 6 weeks. Calories were provided in the form of nutritional supplement bars except for the evening meal that comprised 1/3 of the caloric needs. All subjects were seen and weighed weekly. Metabolic variables including glucose tolerance, glycated proteins, lipids, and percent body fat were measured at the beginning, crossover, and end of the study.

RESULTS

Women with previous gestational diabetes mellitus were comparable to obese women without a history of previous gestational diabetes except that the former had higher maximum levels of glucose on a glucose tolerance test and higher fasting insulin levels consistent with greater insulin resistance. Weight loss was comparable for all groups during the first 6 weeks but attenuated in all groups during the second 6 weeks of the trial regardless of diabetes history or treatment group allocation. Women with or without a previous history of gestational diabetes had higher triglycerides while on a 55% carbohydrate diet than while on a 40% carbohydrate diet.

CONCLUSIONS

A weight loss regimen consisting of 40% carbohydrate results in lower triglyceride levels than those achieved with a 55% carbohydrate content diet in obese women. Thus, the hypocaloric diet with the higher fat content produced the more favorable lipid profile in all obese women.

Waist circumference as a measure for indicating need for weight management

OBJECTIVE

To test the hypothesis that a single measurement, waist circumference, might be used to identify people at health risk both from being overweight and from having a central fat distribution.

DESIGN

A community derived random sample of men and women and a second, validation sample.

SETTING

North Glasgow.

SUBJECT

904 men and 1014 women (first sample); 86 men and 202 women (validation sample).

MAIN OUTCOME MEASURES

Waist circumference, body mass index, waist:hip ratio.

RESULTS

Waist circumference > or = 94 cm for men and > or = 80 cm for women identified subjects with high body mass index (> or = 25 kg/m2) and those with lower body mass index but high waist:hip ratio (> or = 0.95 for men, > or = 0.80 women) with a sensitivity of > 96% and specificity > 97.5%. Waist circumference > or = 102 cm for men or > or = 88 cm for women identified subjects with body mass index > or = 30 and those with lower body mass index but high waist:hip ratio with a sensitivity of > 96% and specificity > 98%, with only about 2% of the sample being misclassified.

CONCLUSIONS

Waist circumference could be used in health promotion programmes to identify individuals who should seek and be offered weight management. Men with waist circumference > or = 94 cm and women with waist circumference > or = 80 cm should gain no further weight; men with waist circumference > or = 102 cm and women with waist circumference > or = 88 cm should reduce their weight.

Effect of somatotropin and feed restriction on body composition and adipose metabolism in obese Zucker rats

The objective of the present study was to determine whether exogenous somatotropin (STH) administration in conjunction with feed restriction could alter the composition of gain in the obese rat. Five-week-old female lean and obese Zucker rats were assigned to the following treatments for 6 wk: ad libitum fed (AL), restricted (approximately 75% of AL lean), and restricted with STH (2 mg STH/day). Growth rate was decreased in restricted groups and was normalized to that of the AL lean group in restricted rats treated with STH. In lean rats, restriction decreased protein accretion. Restriction plus STH treatment decreased lipid accretion but increased protein accretion and body weight gain compared with the AL lean group. As expected, feed restriction reduced body size in obese rats, but carcass lipid was maintained at 44%, a level similar to that of the AL obese rats. Lipid accretion rate was decreased with restriction in obese rats and was further reduced, to a level similar to that of the lean group, in the obese rats that were restricted and treated with STH. Protein accretion was decreased in the restricted obese group but was normalized in those treated with STH to a level similar to that in the AL lean group. Basal rates of lipolysis in isolated adipocytes were not affected by STH. However, STH treatment normalized the responsiveness of cells from the obese rats to stimulation of lipolysis by isoproterenol. The results demonstrate that a combination of caloric restriction and STH was effective in normalizing body weight and composition of gain in the obese Zucker rat.

Obesity in children: recent advances in energy metabolism and body composition

In this paper we review recent advances in energy metabolism and body composition studies in prepubescent children and the relationship to childhood obesity. Our review on energy expenditure focusses on studies of total energy expenditure using doubly labeled water, the role of energy expenditure in the development of obesity, and the determinants of resting energy expenditure in children. The relatively few studies that have examined the regulation of energy and macronutrient intake in children are also reviewed. In terms of body composition, we focus on recent methodological studies that have developed existing techniques for application to the pediatric population, including dual energy X-ray absorptiometry and bioelectrical resistance. Lastly, we review existing information relating to measurement and alteration of body fat distribution in children.

Prediction of adult skinfolds and body mass from infancy through adolescence

In this paper age-to-age correlations for the body mass index and for skinfolds are evaluated for a sample of normal children studied from birth to adulthood. While correlations over larger age spans are modest, they become appreciable from childhood to adolescence and from adolescence to adulthood. Correlations are consistently higher for boys compared to girls, and only for the former does the body mass index correlate better than skinfolds. Significant correlations between weight increase in the first year and the adult body mass index were found, as well as between the age of 'adiposity rebound' and the adult body mass index. However, the small size of the correlations forbids any predictive applications. As it turns out, the individual prediction of the adult size of the body mass index or of skinfolds is a thorny problem, whatever variables and methods are chosen. The precision of such a prediction is very low up to late childhood and becomes somewhat better in adolescence. From a positive side, this leaves much room for overweight children to improve their state. On the other hand, the relative risk for becoming a heavy adult is much increased for those who are already heavy as children and adolescents. This underlines the dangers of early overweight from an epidemiological viewpoint.

Recommended body mass index cutoff values for overweight screening programmes in Australian children and adolescents: comparisons with North American values

OBJECTIVE

Guidelines for screening children and adolescents for overweight have recently been published by a North American Expert Committee. As Australian clinicians might uncritically adopt these recommendations, we explore the consequences of applying North American body mass index (BMI) cutoff values to an Australian population.

METHODOLOGY

The Australian BMI cutoffs were calculated using the methods recommended from height and weight data for 8492 schoolchildren aged 7-15 years old.

RESULTS

Smoothed Australian BMI cutoffs were similar to those derived from the first United States National Health and Nutrition Examination Survey (NHANES-I) values for whites. However, the NHANES-I cutoffs would result in systematic misclassification. Among 7 year olds, the NHANES-I 85th percentile cutoff would wrongly classify 4.6% of normal males and 9.1% of normal females as 'at risk of overweight'. At age 14 years, the NHANES-I 95th percentile cutoff would misclassify 3.5% of children as 'overweight' instead of 'at risk of overweight'.

CONCLUSION

Australian screening programmes should use BMI cutoffs appropriately derived from local measurements, and these are given for Australian children.

Insulin and colon cancer

Some factors related to Westernization or industrialization increase risk of colon cancer. It is believed widely that this increase in risk is related to the direct effects of dietary fat and fiber in the colonic lumen. However, the fat and fiber hypotheses, at least as originally formulated, do not explain adequately many emerging findings from recent epidemiologic studies. An alternative hypothesis, that hyperinsulinemia promotes colon carcinogenesis, is presented here. Insulin is an important growth factor of colonic epithelial cells and is a mitogen of tumor cell growth in vitro. Epidemiologic evidence supporting the insulin/colon-cancer hypothesis is largely indirect and based on the similarity of factors which produce elevated insulin levels with those related to colon cancer risk. Specifically, obesity--particularly central obesity, physical inactivity, and possibly a low dietary polyunsaturated fat to saturated fat ratio--are major determinants of insulin resistance and hyperinsulinemia, and appear related to colon cancer risk. Moreover, a diet high in refined carbohydrates and low in water-soluble fiber, which is associated with an increased risk of colon cancer, causes rapid intestinal absorption of glucose into the blood leading to postprandial hyperinsulinemia. The combination of insulin resistance and high glycemic load produces particularly high insulin levels. Thus, hyperinsulinemia may explain why obesity, physical inactivity, and a diet low in fruits and vegetables and high in red meat and extensively processed foods, all common in the West, increase colon cancer risk.

Impact of antiseizure medication level on the incidence of sudden unexplained death from epilepsy in patients from an inner city emergency department

Sudden unexplained death from seizures (SUDS) accounts for death in approximately 10% of the epileptic population. SUDS usually occurs in young males with a history of seizure disorders who are in otherwise good health. No definitive anatomical lesions are found at autopsy that explain death. There is however, a correlation between SUDS and subtherapeutic levels of antiseizure medications. The purpose of this study was to retrospectively review and compare drug levels from a seizure patient that presented to an inner city emergency department to those from the medical examiners office. This study was prompted by a wrongful death claim for substandard care in a known seizure disorder patient. The claim alleged that the death was directly attributed to subtherapeutic seizure medication levels. We report the results from 150 seizure patients that presented to the emergency department with a chief complaint of a recent seizure and of 163 patients that were examined post mortem. 58% of the emergency department patients who were taking phenytoin, 79% taking carbamazapine and 82% of the patients taking phenobarbital had subtherapeutic levels. No patient in this population died and only 13% required hospital admission. These levels were comparable to the post mortem population.

Sex-specific effects for body mass index in the new Norwegian twin panel

Sex-specific effects for body mass index (BMI) were explored in a newly established, population-based Norwegian twin panel. The sample includes 5,864 individuals, aged 18-25 years, who responded to a questionnaire containing items for zygosity classification, height, weight, health, health-related behaviors, well-being, and demographic information. Among the 2,570 intact pairs who returned the questionnaire there were 416 identical (MZ) male pairs, 387 fraternal (DZ) male pairs, 528 MZ female pairs, 443 DZ female pairs, and 796 unlike-sexed pairs. Alternate sets of models testing for either sex-specific genetic or environmental parameters were evaluated using structural equation analysis. Results from the most parsimonious model indicated that the genes contributing to variation in BMI are not identical for men and women; rather, some genetic effects were shared by the sexes and some were unique to each sex. Total variation in BMI could be explained by sex-specific additive genetic effects, as well as genetic and non-shared environmental effects common to men and women. Estimates of heritability were .708 for men and .789 for women, and the male-female genetic correlation was 0.622. The series of models specifying sex-specific shared environment also fit the data and suggests that shared environmental factors may be important for males but not for females. The findings raise questions concerning the relationship between sex-specific effects for BMI and sex differences in health outcomes.

Dietary factors and risk of colon cancer

The incidence rates of colon cancer are high in North America and northern Europe, lower in southern Europe, and much lower in Asia and Africa. It is widely believed that environmental factors, particularly dietary patterns, account for most of this marked variation in rates. Over the past decade, a large number of case-control and cohort studies have added a substantial body of evidence regarding our understanding of the causes of colon cancer. Although the data are not entirely consistent, several important risk factors have emerged. The epidemiological evidence that physical inactivity or excess energy intake relative to requirements increases risk of this malignancy is quite strong. Intake of red meat appears to increase risk, but protein-rich sources other than red meat probably do not elevate risk and may even reduce the occurrence of colon cancer. Dietary fat, at least that from sources other than red meat, does not appear to increase risk appreciably. High consumption of vegetables and fruits and the avoidance of highly refined sugar containing foods are likely to reduce risk of colon cancer, although the responsible constituents remain unclear. Alcohol intake may enhance risk of cancers of the distal colorectum, although the evidence is not entirely consistent. The influence of alcohol may be particularly strong when combined with a diet low in methionine and folate, suggesting that the effect of alcohol may be through antagonism of methyl-group metabolism. The combined effect of these dietary factors, as well as modifiable non-dietary factors such as cigarette smoking, suggest that the majority of cases of colon cancer are preventable.

Relationships between the fatty acid status and insulinemic indexes in obese children

The relationship between the fatty acid (FA) status and indices of insulin secretion in young obese subjects at risk of developing insulin resistance and its complications was investigated. In 12 subjects (8-14 years) at first diagnosis of obesity the FA composition of total plasma and circulating and erythrocyte phospholipids was related to basal and peak insulinemia and the insulinemic area resulting from a standard oral glucose tolerance test. Negative correlations were shown between both delta-6-desaturation products and 20:5 n-3 levels and insulinemic values. On the contrary, circulating total saturated and monounsaturated FA and erythrocyte phospholipid products of delta-5- and delta-4-desaturation positively correlate with insulinemic indices. The observed relationships could be markers of developing insulin resistance and suggest the possibility of a dietary intervention.

Treatment of hypertension in children

This review summarizes the current approach to antihypertensive therapy in children. It focuses on newer drugs, taking into account changes in clinical practice that have occurred since publication of the second Task Force report. Non-pharmacological therapy, including weight reduction, exercise, and dietary intervention, has great potential for the effective reduction of blood pressure. It should be introduced not only in patients with "significant" hypertension, but also in the care of patients with high normal blood pressure and to complement drug therapy for patients with "severe" hypertension. The goal of antihypertensive drug therapy is reduction of blood pressure to a level below the 95th percentile for age and sex. Attempts to rapidly achieve normal blood pressure immediately after starting therapy are contraindicated. The objective of emergency treatment is prevention of hypertension-related adverse events, and this usually requires only a modest reduction in blood pressure. Nifedipine has become the most commonly used drug for emergency treatment of asymptomatic children. Exceptionally severe elevations of blood pressure or the presence of symptoms should be treated with more potent intravenous drugs. The converting enzyme inhibitors and calcium channel blockers currently are the primary agents for chronic treatment of hypertension in children. Diuretics are usually reserved for hypertensive patients with renal disease. beta-Adrenergic blocking drugs also are effective but have a number of potential adverse effects. Prazosin generally is used as a second-line agent, if the above-noted drugs are ineffective. Although minoxidil is still one of the most effective antihypertensive agents, its associated adverse effects have limited its usefulness.

Obesity among young Saudi female adults: a prevalence study on medical and nursing students

The prevalence of obesity was examined among Saudi female medical and nursing students. The analysis was made on 222 students whose ages ranged from 18-25 years. Standard procedures for measuring weight, height and triceps skinfold measurements were conducted. The criteria for obesity used in the present study were: (i) body mass index (W/H2) in kg/m2 > or = 25 and (ii) triceps skinfold measurement of > or = 25 mm (> or = 85th percentile for ages 18-24 years). The prevalence rate of obesity by body mass index was found to be 30.6% with more girls falling in the Grade I (26.1%) than the Grade II (4.5%) category. Using the skinfold measurement as a standard, a smaller proportion (16.8%) of students was observed to be obese indicating variation in the sensitivity of the two indices as measures of body fatness. Irrespective of the method used for estimation, the prevalence of obesity in these young Saudi women was notably high and supports findings of earlier studies for a common occurrence of female obesity in this region. Preventive programmes for weight control and a healthy lifestyle among Saudi females should be emphasised from young adulthood or perhaps earlier.

Preventing obesity in black women by targeting adolescents: a literature review

Obesity is a critical problem in black women. Black women have been found to have twice the rate of obesity of white women, and the origins of obesity appear to be in adolescence. To date, few obesity prevention and treatment programs have been designed specifically for black female adolescents and black women. In this review, the biopsychosocial factors surrounding obesity in the black female population are discussed, including the significance of body fat distribution for the development of diseases common to the black population, such as diabetes and hypertension; the cultural tolerance for overweight and obesity in black women; and the importance of family and social networks in the dissemination of health information. Programs that stress early intervention during adolescence are identified as having the most potential to make an impact on obesity in black women and, ultimately, to reduce chronic disease. However, such interventions must be sensitive to cultural belief systems and values. The need to eliminate a predominantly white, Anglo-Saxon, ethnocentric viewpoint to prevent and treat obesity in black female adolescents is stressed.

Dairy products and adolescent nutrition

Adolescence is an intense anabolic period. The requirement for all nutrients is increased, but particularly that for dietary calcium. A balanced intake of the macronutrients (protein, fats and carbohydrates) is recommended to prevent the chronic degenerative disorders of adulthood. The temporal pattern of the calorie intake also deserves attention since it may affect homeostatic regulation. Adolescents often show disorders of dietary behaviour predisposing them to both obesity and anorexia. Dietary intervention in this age-group should promote the regular consumption of breakfast, a balanced intake of animal and vegetable foods and an increased calcium supply to maximize bone density. Dairy products and vegetables (mainly enriched cereals) constitute the basis of a good diet for adolescents, to supply their needs for growth and for subsequent good health.

Effects of mastery criteria and contingent reinforcement for family-based child weight control

This study tested the effects of mastery criteria and contingent reinforcement in a family-based behavioral weight control program for obese children and their parents over two years. Families with obese children were randomized to one of two groups. The experimental group was targeted and reinforced for mastery of diet, exercise, weight loss, and parenting skills. The control group was taught behavior-change strategies and provided noncontingent reinforcement at a pace yoked to the experimental group. Both groups received the same behavioral family-based educational components over 6 months of weekly meetings and six monthly follow-up meetings. Results showed significantly better relative weight change at 6 months and 1 year for children in the experimental compared to the control group, but these effects were not maintained at 2 years. These results suggest the introduction of mastery criteria and contingent reinforcement for mastery can improve outcome during treatment in behavioral treatments for childhood obesity.

Why do we eat?

The urge to eat is the main apparent issue underlying obesity. Although vast information regarding the physiology and psychology of eating behavior has been accumulated, a comprehensive concept is still missing. The model presented suggests that feeding behavior is ultimately controlled by the rate of work performed in the muscle or in an as yet unidentified compartment. It suggests a novel approach of a dynamic set-point weight and explains why diets usually fail to resolve the disorder while physical activity is beneficial in losing excess weight. Obesity is presented as a syndrome of high efficiency of energy conversion resulting in a variety of symptoms of which over-weight is only the more apparent. Other symptoms manifested in the predisposition to a variety of illnesses constitute the main health problem and can prevail in the obese subject even without the excess weight. Therefore, resolution of the disorder requires developing approaches which directly affect the efficiency of energy conversion.

The weight and fitness status of United States children

Although the prevalence of overweight and obesity among US children is a concern for many health care professionals, incidence rates over time seem to be variable, depending on the assessment measurements used. It is difficult to determine the associated health implications of pediatric obesity or overweight, especially the type that might result in adult obesity or overweight. This review examines the various factors that contribute to the weight and fitness status of children, including anthropometric factors, nutrient intake, the level of physical activity, and nutrition knowledge. Nutrient intake data of the past decade show that the energy and fat intakes of children in the United States have been fairly constant. However, data also indicate that their physical activity has declined. The data strongly suggest that the apparent prevalence of pediatric overweight may not be so much a function of nutrient intake as of a decrease in physical activity leading to an imbalance of energy input and output.

Risk factors for obesity in young adults: Hispanics, African Americans and Whites in the transition years, age 16-28 years

Previous studies have suggested that late adolescence may represent a critical period in the development of lifelong obesity, but representative prospective studies in this age group are lacking. The analytic cohort consisted of a representative sample from the United States of 11,591 Hispanic, African American, and white youths interviewed as part of the National Longitudinal Survey of Youth. Significant differences in obesity measures were observed among the six race-sex groups. Compared to whites of the same sex, the prevalence of obesity in 1981 was significantly higher among Hispanic males (12.0 vs 8.6%, P < 0.05) and African American females (14.2% vs 7.3%, P > 0.001) and lower among African American males (6.4% vs 8.6%, P > 0.005). Five-year cumulative incidence of obesity (1981-1986) was highest in Hispanic males, Hispanic females and African American females. Among those ages studied both in 1981 and in 1986, a secular trend towards increased prevalence of obesity was observed over the five-year period (10.6% in 1981, 13.6% in 1986, P > 0.0001). Multivariate analyses failed to identify behavioral or sociodemographic factors that operated similarly in all race-sex groups.

Does early physical maturity influence breast cancer risk?

Earlier onset of menarche and tallness in adult women are mainly confirmed as risk markers for breast cancer. Recent disparate case-control studies have reported abdominal-type obesity and higher circulating levels of insulin, testosterone and insulin-like growth factor 1, to be further risk markers for breast cancer. There is evidence that abdominal-type obesity is recognisable in girls even before puberty, and disparate studies have shown it to be correlated with earlier onset of menarche, insulin resistance leading to hyperinsulinaemia, and an abnormal sex steroid profile. The implications are that earlier onset of puberty in a subset of girls can lead to more prolonged exposure of developing breast tissue to an abnormal sex steroid profile and also to a higher circulating level of insulin. It is postulated that these metabolic/endocrine concomitants of abdominal-type obesity could play a role in promoting mammary carcinogenesis at a young age, particularly if genetic predisposition is present.

Recent advances in the treatment of childhood obesity

The multidisciplinary, four-phase approach, which includes PSMF, BEM, and MPE is successful in treating mild, moderate, and severe degrees of childhood and adolescent obesity. The MPE program is appropriate for use with PSMF and BEM due to its progressive nature, variety of options, and moderate intensity level. In addition, the MPE program is of sufficient intensity, duration, and frequency to promote a significant increase in estimated aerobic capacity (VO2max) and to promote the maintenance of lean body mass and resting energy expenditure. The short-term intervention of PSMF, BEM, and MPE also results in an improvement in body composition, lipid profiles, and IGF-1 and T3 levels. The 1200-calorie balanced diet, MPE, and BEM also provide a successful method of weight maintenance in children and adolescents, as indicated by further improvement in body composition at the 26-week measure. Additional studies are needed to assess the contribution of exercise to the maintenance of lean body mass and resting energy expenditure in obese children and adolescents. In addition, it will be important to assess long-term weight maintenance in obese adolescents who effectively lose weight in this multidisciplinary program.

Social and economic consequences of overweight in adolescence and young adulthood

BACKGROUND AND METHODS

Overweight in adolescents may have deleterious effects on their subsequent self-esteem, social and economic characteristics, and physical health. We studied the relation between overweight and subsequent educational attainment, marital status, household income, and self-esteem in a nationally representative sample of 10,039 randomly selected young people who were 16 to 24 years old in 1981. Follow-up data were obtained in 1988 for 65 to 79 percent of the original cohort, depending on the variable studied. The characteristics of the subjects who had been overweight in 1981 were compared with those for young people with asthma, musculoskeletal abnormalities, and other chronic health conditions. Overweight was defined as a body-mass index above the 95th percentile for age and sex.

RESULTS

In 1981, 370 of the subjects were overweight. Seven years later, women who had been overweight had completed fewer years of school (0.3 year less; 95 percent confidence interval, 0.1 to 0.6; P = 0.009), were less likely to be married (20 percent less likely; 95 percent confidence interval, 13 to 27 percent; P < 0.001), had lower household incomes ($6,710 less per year; 95 percent confidence interval, $3,942 to $9,478; P < 0.001), and had higher rates of household poverty (10 percent higher; 95 percent confidence interval, 4 to 16 percent; P < 0.001) than the women who had not been overweight, independent of their base-line socioeconomic status and aptitude-test scores. Men who had been overweight were less likely to be married (11 percent less likely; 95 percent confidence interval, 3 to 18 percent; P = 0.005). In contrast, people with the other chronic conditions we studied did not differ in these ways from the nonoverweight subjects. We found no evidence of an effect of overweight on self-esteem.

CONCLUSIONS

Overweight during adolescence has important social and economic consequences, which are greater than those of many other chronic physical conditions. Discrimination against overweight persons may account for these results.

The role of weight management in the health of women

Weight management plays a central role in preventing many diseases that affect women. Lifelong hormonal, psychological, and environmental influences on women elicit a set of behavioral and biological responses distinctive from men that place them at increased risk for overall weight concerns, weight gain, and obesity. Limitations of current treatment call for increased research to improve our understanding and guide efforts in this important aspect of women's health. Research needs to be conducted to define realistic and obtainable weight goals and to design educational strategies to promote health and self-esteem. Research in the field of weight management should be directed to understanding gender differences, etiologies, and effective treatments.