Overweight and obese children have low bone mass and area for their weight

Abstract

OBJECTIVES: To determine whether girls and boys categorized from body mass index (BMI) values as overweight or obese for their age have lower bone mineral content (BMC) or lower bone area in relation to total body weight than children of normal adiposity. DESIGN: Cross-sectional study in a university bone research unit. SUBJECTS: Two hundred girls and 136 boys aged 3 ± 19 y recruited from the general population by advertisement. MEASUREMENTS: Total body BMC (g) and bone area (cm 2 ) measured by dual energy X-ray absorptiometry (DXA) in relation to body weight (kg), lean tissue mass (kg) and fat mass (kg) in boys and girls of three different BMI percentile groupings: normal weight (BMI`85th percentile); overweight (85 to 94th BMI percentile); obese ( 95th BMI percentile). RESULTS: Obese children had higher BMC, bone area, and fat mass for chronological age than those of normal body weight (P`0.001). In spite of this the observed values for age-adjusted total body BMC and bone area relative to body weight were each lower than predicted values, in both overweight and obese children (2.5 ± 10.1% less, P`0.05) than in children of lower adiposity. CONCLUSION: In overweight and obese boys and girls there is a mismatch between body weight and bone development during growth: their bone mass and bone area are low for their body weight.

Evaluation of lean tissue density for use in air displacement plethysmography in obese children and adolescents

“…Hydration is increased, and D LT lower, in obese compared with normal weight individuals (Haroun et al, 2005). These differences have been attributed in part to expansion of the extracellular water space (Battistini et al, 1995), which in turn reflects irreversible changes in hemodynamics (Marken Lichtenbelt and Fogelholm, 1999;Leone et al, 2000); but also in part to reduced mineralisation (Goulding et al, 2000). Thus, values for the hydration or D LT obtained from individuals within the normal range of body weight will not transfer successfully to those obese.…”

Childhood Obesity Is Associated With Increased Risk of Most Lower Extremity Fractures

“…Several studies have shown that obese adults have increased bone density [16,23]. Given the somewhat conflicting results in previous studies showing that obese children either have increased bone density [6,7,15,24,25] or decreased bone density/mass or bone mineral content relative to body size [11,12], it may be that some older obese children could have an increased bone density, similar to the pattern seen in obese adults. The inconsistent association between obesity and fractures of the proximal femur and femoral shaft was the other interesting finding in this study that was different than most of the rest of the data indicating a relationship between increasing obesity and increasing fracture risk.…”

Obesity and fracture in men and women: An epidemiologic perspective

“…In some reports, obese children with fracture had somewhat higher levels of radial bone mineral content (BMC) (32) while in others, fractured kids had lower BMC. (33,34) Increased risk of fracture in overweight children may be because of greater fall forces or a greater tendency to fall, but other effects of fat on bone maturation have also been invoked as a potential explanation. (1,4) In older adults, the meta-analysis by De Laet and colleagues (11) found that after BMD adjustment there was a small but significant protective effect of higher BMI on hip fracture in women but not in men.…”