The chronic disease of childhood obesity: the sleeping giant has awakened

Nonalcoholic fatty liver disease (NAFLD) in children

Nonalcoholic fatty liver disease (NAFLD) is common in obese children and is a growing problem, given the increase in prevalence of obesity. NAFLD is also associated with diabetes, insulin resistance, hypercholesterolemia, and hypertriglyceridemia. Although mostly benign, some children with NAFLD develop fibrosis and cirrhosis, which necessitates close monitoring. Chronically elevated plasma liver enzyme levels is the most frequent finding. Ultrasound (US) examination allows confirmation of the diagnosis and it is useful for the follow-up. Gradual and sustained weight reduction is a management option that is worth trying initially. Other modalities of management, although interesting, await evidence as well as information on long-term benefits and effects. Sustained increase of transaminases despite weight reduction is a cause for concern and may require a liver biopsy both to assess severity of liver damage and for prognostic purposes.

The contribution of fat and fat-free tissue to body mass index in contemporary children and the reference child

BACKGROUND

Body mass index (BMI) is widely used to assess the prevalence of childhood obesity in populations, and to infer risk of subsequent obesity-related disease. However, BMI does not measure fat directly, and its relationship with body fatness is not necessarily stable over time.

OBJECTIVE

To test the hypothesis that contemporary children have different fatness for a given BMI value compared to the reference child of two decades ago.

DESIGN

Comparison of children from Cambridge, UK with the reference child of Fomon and colleagues (Am J Clin Nutr 1982; 35: 1169-1175).

SUBJECTS

A total of 212 children aged 1-10.99 y.

MEASUREMENTS

Body composition was assessed by deuterium dilution. Fat-free mass and fat mass were both adjusted for height to give fat-free mass index and fat mass index.

RESULTS

Contemporary Cambridge children have similar mean BMI values to the reference child. However, both boys and girls have significantly greater mean fatness and significantly lower mean fat-free mass than the reference child after taking height into account. Contemporary Cambridge children have greater fatness for a given BMI value than the reference child.

CONCLUSION

BMI-based assessments of nutritional status may be under-estimating the increase in children's fatness. Any change over time in the relationship between BMI and body fatness will create a mismatch between (1) current estimates of childhood obesity and (2) predicted risk of future adult illness, calculated on the basis of longitudinal cohorts recruited in childhood several decades ago. However, an alternative interpretation is that the reference data are inappropriate. Caution should therefore be used in generalizing from this study, and further investigations of the issue are required.

Metabolic correlates with obstructive sleep apnea in obese subjects

OBJECTIVE

To examine links between obstructive sleep apnea (OSA), insulin resistance, and dyslipidemia.

STUDY DESIGN

Obese (body mass index [BMI] >95th percentile for age and gender) children who snored (n = 62, 46 males, age 10.89 [5-16 years] underwent polysomnography and metabolic studies.

RESULTS

Respiratory disturbance index (RDI) was 9.23 (0-95), with 23 children (39%) recommended for treatment. Fasting insulin levels were 154.6 pmol/L +/- 79.8 (52-486), and fasting glucose levels were high in 7 children (11%). Fasting insulin levels correlated with sleep variables, including log transformed RDI (log(10)RDI) (P =.01), desaturation events (P =.05), arousal index (P =.01), and sleep-time with oxygen saturation in arterial blood <90% (P =.03) (adjusted r (2) = 0.21, F = 3.9, P =.005), but not with age, or BMI Z score. Log(10)RDI correlated with fasting insulin (P =.001) and BMI Z score (P =.03) (adjusted r (2) = 0.12, F = 3.9, P =.005), but not age or other metabolic variables. The correlation between log(10)RDI and fasting insulin persisted in models combining sleep and metabolic variables: log(10)RDI, adjusted r (2) = 0.75, F = 35.2, P <.001, and for fasting insulin, adjusted r (2) = 0.42, F = 6.1, and P <.001.

CONCLUSIONS

The severity of OSA (log(10)RDI) correlated with fasting insulin levels, independent of BMI. Insulin levels may be further elevated as a consequence of OSA in obese children.

Pediatric liver disease in the United States: epidemiology and impact

Liver diseases which affect children are unique. Diseases such as inborn errors of metabolism are fertile grounds for investigation. Study of these 'experiments of nature' will provide insight into hepatobiliary function and lead to novel treatment modalities. Successful treatment or prevention of liver disease in children will have long-term implications. This report describes the current burden of pediatric liver disease and offers approaches to intervention.

An obligation for primary care physicians to prescribe physical activity to sedentary patients to reduce the risk of chronic health conditions

Physical inactivity increases the risk of many chronic disorders. Numerous studies have convincingly demonstrated that undertaking and maintaining moderate levels of physical activity (eg, brisk walking 3 hours a week) greatly reduces the incidence of developing many chronic health conditions, most notably type 2 diabetes mellitus, obesity, cardiovascular disease, and many types of cancers. However, the underlying mechanistic details of how physical activity confers such protective effects are not well understood and consequently constitute an active area of research. Although changing an individual's ingrained behavior is commonly perceived to be difficult, encouraging evidence suggests that intensive and repeated counseling by health care professionals can cause patients to become more physically active. Therefore, counseling patients to undertake physical activity to prevent chronic health conditions becomes a primary prevention modality. This article summarizes the vast epidemiologic and biochemical evidence supporting the many beneficial health implications of undertaking moderate physical activity and provides a rationale for incorporating physical activity counseling as part of routine practice in the primary care setting.