Obesity in Down syndrome patients: causes and management

Down Syndrome and Obesity

Downs syndrome and Obesity

Existing literature has clearly identified a positive correlation between Down syndrome and obesity as a coexisting condition. Though by themselves obesity and downs syndrome have a depth of research material there is a distinct lack of research when it comes to studying the association between them. More research is required for understanding the onset of obesity among the intellectually disabled patients. Weight management interventions constitute an important aspect in the management of down's syndrome and other related intellectual disabilities. Only a coordinated effort from professionals from the fields of Obesity and intellectual disabilities would provide the necessary expertise and ensure quality care provision for patients suffering from such debilitating health conditions

Introduction

Down's syndrome also known as trisomy 21, is one of the chromosomal disorders that result in significant mental and physical disabilities. In the UK, one in every 1000 babies is born with the condition. Infants with the condition are born with an extra copy of the chromosome number 21 causing considerable aberrations in the development of physical and cognitive faculties. [BUPA] Symptoms are varied and it is known that there are more than 50 characteristics that symptomatically identify Down's syndrome. Typical symptoms include short stature, small neck, short stocky arms the presence of a single crease across the palm known as the simian line. Weak muscles, distorted nose and irregular teeth are other easily visible symptoms of the disorder. The prevelance of heart diseases and early onset of alzheimer's disease are common conditions among the down's syndrome population. In general, people with Down syndrome have a relatively shorter span of life with an average of fifty years. Another significant health problem, the condition of obesity, is also found to be more prevelant among people with Down syndrome. In early infancy about 15% of neonates become overweight, about 30 to 50% become overweight by 36 months, and by 9 years of age most of the Down syndrome children are overweight. [Jacqueline Bauer et.al] This very high rate of obesity among people with Down syndrome necessitates more research to identify the cause for the problem and in effective management of obesity and its complications.

Some researchers have focused on identifying the relation between Down syndrome and obesity as a co existing condition. Studies have been conducted to identify the differences in metabolic rates between the Down's syndrome patients and the healthy population. The most recent research has thrown new light in understanding the relation between Down syndrome and obesity. The identification of Leptin resistance as the cause for high incidence of obesity among Down syndrome patients is considered a breakthrough in the obesity -Down syndrome research. A brief overview of existing literature on the subject will provide better insight into the topic and a better understanding of the association between the two conditions.

Metabolic studies

Studies have also focused on the metabolic rates in people with Down syndrome and its effect on increased body weight and obesity. There is a generally accepted notion that children with Down syndrome have lower metabolic rates compared to normal children. Several studies have been examining this subject in detail but the results seem to be quiet varied. For instance, Luke et.al (1994) was one of the oldest studies, which compared 13 prepubescent children with DS with 10-control group children within the same age group. The study reported no significant difference in non-RMR energy expenditure but showed a significant difference in resting metabolic rate (RMR) between the two groups. As a percentage of the basal metabolic rate, the Down's syndrome children showed relatively lesser RMR rates. (79.5% +/- 10.4% and 96.8% +/- 7.8%, p < 0.001). [Luke a, 1994] However, more recent studies show completely different results. The 2005 study by Fernhall B. et al. compared the RMR of 22 subjects with Down's syndrome with that of 20 normal control subjects within similar age group. Both the groups were fasted the previous night and using the ventilated hood system RMR was measured in the morning. After adjustments to RMR in relation to body surface area, it was found that there was no significant difference in RMR between the two groups suggesting a negative association between RMR and obesity among subjects with Down's syndrome. [Fernhall B. et al., 2005]

Jacqueline et.al (2003) was a different study on neonatal energy expenditure among patients with Down syndrome in their early infancy. They study included 16 neonates, 8 of them normal and eight with Down syndrome. (Diagnosis confirmed by chromosomal studies) the subjects chosen were of similar gestational age, birth weights and body length. Neurological examination, oxygen consumption and carbon dioxide production along with nutrition and weight were measured regularly. Using calorimetry the EE (energy expenditure) and REE (resting energy expenditure) data were obtained and compared for each group. The study showed a considerable reduction in VO2, VCO2, and REE values in babies with Down syndrome in their first week of postnatal life. EE values were 10% lower in Down syndrome patients compared with normal babies. Neonatal heartbeats were also found to be lower in Down syndrome babies (6 beats less per min on an average). The researchers found that REE was 14% lesser than healthy infants of comparable age. [Jacqueline et.al, 2003] more recent study aimed at understanding the differences in weight among normal people and the intellectually disabled population was conducted by the Leicestershire NHS Partnership Trust and the Department of health. This was an extensive study which included 1119 ID subjects registered in the Leicestershire database and comapred their BMI data with non-intellectualy disabled subjects in the region. The data obtained indicated that among those aged 20 and above, the prevelance rates for obesity, overweight, normal weight, and underweight were 20.7%, 28%, 32.7% and 18. 6% respectively. From the data that was gathered it was clear that obesity was positively associated with downs syndrome and being a female was a high risk factor. Also, the researchers found absence of Down's syndrome as a clear factor in the case of underweight conditions. This research further confirmed that having down's syndrome predisposes one to obesity. [Sabyasachi Bhaumik et.al, 2007]

Obesity Screening and Health promotion Impact recent study in northern ireland was undertaken to identify the effect of screening programs and other health intervention programs for intellectually disabled people. Screening programs were conducted by 2 disability nurses for around 464 people aged over 10 years and attending special services in the region. It was found that around 64% of adults and 26% of those between 10 and 19 were either overweight or obese.

However, a follow up survey after 3 months indicated that of the 122 people identified and recommended for weight reduction programs only 34% participated in the program and only 3 among them achieved weight reduction. This study pointed out that screening programs by themselves are ineffective without any followup. In case of people with intellectual disabilities like Down's syndrome, obesity presents a huge problem and a collaborative effort is required for effective health promotion. [Marshall D. et.al, 2003]

Outcome for fitness and health education programs were effective among Down syndrome patients in Heller et.al (2004). In a randomised trial of 53 subjects, (29 females and 24 males) 32 subjects were randomly assigned to the program group while 21 subjects were in the control group. After the completion of a 12-week at 3 days per week training program, the subjects showed significant improvement in self-efficacy, expressed increased interest in exercise programs, displayed cognitive improvements, decreased depression levels and an overall improvement in positive outcomes. [Heller, 2004]

Conclusion

Down's syndrome is a common chromosomal disorder and a debilitating one. Asides the cognitive impariments, the disorder also causes obesity, another major health concern. With majority of the down syndrome population falling into overweight or obese conditions, the consequent health issues assume great significance. Background obesity is thus a huge problem in patients with intellectual disabilities, and in particular, Down's syndrome. Some of the studies reviewed above also showed a greater predisposition among females than males in contracting obesity due to Down's sydnrome. Though there is considerable amount of research devoted to obesity or Down syndrome seperately there is a dearth of research when it comes to studying the association between them. Some studies have been more generalized discussing the whole spectrum of Intellectual disabilities and obesity. The few studies which have been specifically devoted to Down's syndrome and its relation to obesity have so far indicated a positive correlation between them. More research is required to identify the causes that result in the onset of obesity among such intellectually disabled patients. The recent research that identified Leptin resistance as the main cause for obesity among Down syndrome patients is a positive breakthrough in the research on down syndrome. Very soon, pharmacological interventions would be targetted at rectifying this leptin resistance and then obesity may cease to be a coexisting condition. However, that would necesitate a better understanding of the molecular mechanics behind leptin resistance.

In future, with the advancements in genomic science and stem cell therapy it would be possible to completely cure this genetic disorder but such a cure remains a distant dream at this moment. Until such time it is necessary to provide better interventions and support to the affected people. Weight management interventions constitute an important aspect in the management of down's syndrome and other related intellectual disabilities. Inorder to provide more effective treatment and better services to such patients there is a necessity for professionals representing these different fields to work together. Only such a coordinated effort from professionals from the fields of Obesity and intellectual disabilities would provide the necessary expertise and ensure quality care provision for the patients suffering from such debilitating health conditions.