Childhood obesity: medical, cultural and psychological factors

Abstract

The aim of this thesis was to examine medical, cultural and psychological factors of childhood obesity in a multi-ethnic cohort.

Medical factors Several associations between weight measured and hormones were determined in obese children between 6 and 18 years. Thyroid stimulating hormone (TSH) was associated with age and sex standardized body mass index (Z-BMI), impaired fasting glucose, impaired glucose tolerance, high total cholesterol, high LDL-cholesterol and high triglycerides. There were no significant associations between albumin/creatinine ratio and any cardiometabolic risk factors. Moreover, there was a low prevalence of microalbuminuria (an early marker of kidney disease). In contrast, an alarmingly high prevalence of vitamin D deficiency was found in obese ethnic children (88%), while normal weight white children showed a prevalence of 20%. With a high loading dose of 25 000 IU weekly vitamin D3 supplementation, 84.4% of these children improved from deficiency (<50 nmol/L) to sufficiency (≥50 nmol/L). No side effects were reported, and the highest level reached was far below the threshold for toxicity.

Cultural and family factors The radical change in lifestyle during Ramadan has shown to affect the weight, glucose and lipid metabolism in normal- and overweight adults. We found that Ramadan 2012 had no effect on Z-BMI or glucose metabolism in 25 obese adolescents. However, transient increases in total-, LDL-, HDL-cholesterol and hs-CRP were observed, all of which normalized 6 weeks after conclusion of Ramadan fast. Parental weight has proven to be one of the most important independent predictors of childhood obesity and therefore we determined the effect of gastric bypass on the weight and eating behaviors of their children. Surprisingly, no significant changes in eating behavior or Z-BMI of the children were found after one year.

Psychological factors

In addition to the physical health problems, obesity also poses a considerable risk of psychological problems. Indeed, health related quality of life and specifically the subscales physical wellbeing, moods & emotions and self-perception were markedly reduced in our obese cohort compared to an age and sex matched reference group. Parents reported consistently lower quality of life scores than the children themselves. Surprisingly, we did not find any ethnic specific differences in quality of life. Furthermore, obese children had more eating- and overall behavior problems compared to normal weight children. Moreover, obesity was significantly associated with poor intelligence, poor working memory and high response variability. Response variability was correlated with inattention, a well known symptom of attention-deficit/hyperactivity disorder (ADHD). These results suggest that ADHD like symptoms could be a risk factor for the development of obesity, which need to be confirmed by future longitudinal studies.