The problem of obesity and the onset of Type 2 diabetes in children

2 February, 2002

Margaret Perry, BSc (Hons), RN, Nurse Practitioner Dip (HE).

Trainee Advanced Nurse Practitioner, Whiteheath Clinic, Oldbury, West Midlands

Obesity is a problem that appears to be increasing in prevalence not only in the UK but in several other nations around the world. The National Audit Office has recently issued its report Tackling Obesity in England (NAO, 2001).

Obesity is not confined to adults - statistics from Europe and the USA show that one in four cases seen by paediatricians are children with weight problems (Fruhbeck, 2000). In the USA, diabetic clinics are reporting that 8-45% of new cases of diabetes in children are Type 2, and in some clinics new cases of this condition in adolescents are outnumbering those of Type 1 (Fruhbeck, 2000).

Obesity in adults is an acknowledged risk factor for Type 2 diabetes and, although obesity has long been recognised in children, Type 2 diabetes was thought not to develop in this age group - its onset is typically assigned to adults aged over age 40 (Pinhas-Hamiel, 2001). Rising levels of obesity in children and adolescents have led to several recently identified cases of Type 2 diabetes in this age group. The concern is that, if this cycle of obesity and younger onset of the disease continue at the present rate, these children will be at a similar risk of microvascular and macrovascular complications associated with adult-onset diabetes (Ng and Burren, 2000).

Signs and symptoms
The clinical picture for these children differs sharply from that seen in Type 1 diabetes, where presentation is often acute and requires immediate medical intervention to correct dehydration and keto-acidosis.

There are, however, several similarities with adult-onset Type 2 diabetes, with the exception of one or two clinical features which are specific to adolescent onset. The condition has an insidious onset, and may be asymptomatic, with little evidence of thirst or polyuria, which is often a feature in adults.

Obesity is a key feature and these children are often considerably heavier than the recommended weight for their height. Glycosuria is present and, on further examination, there may be evidence of hypertension and hyperlipidaemia and elevated glycated haemoglobin (HbA1c) results.

Acanthosis nigricans has been identified in several children with this condition and is regarded as an indicator of insulin resistance (Ng and Burren, 2000). This is a dermatological condition that manifests as pigmented, thickening of the skin, with associated warty lesions, predominantly found in the axilla and the groin (Hope et al, 1994). It has been identified as a clinical finding in up to 90% of affected children (Shaw, 2001).

Females may have polycystic ovary syndrome and hirsutism (Ehtisham et al, 2000) and report menstrual disturbances on questioning.

A family history of diabetes appears to be a key factor. Some 45-80% of cases have at least one parent with diabetes and often have a history of diabetes spanning several generations (American Diabetes Association, 2000).

Differential diagnosis
Maturity-onset diabetes of the young (MODY) is a rare condition, with symptoms having some similarity to those seen in children with Type 2 diabetes, but its development is genetically determined. Five genes have been identified to date that are believed to account for approximately 80% of all cases of MODY in the UK (Hattersley et al, 1998). The clinical features vary according to the gene affected, as does the level of treatment required and the risk of developing the complications of diabetes.

Diagnosis of Type 2 diabetes in children
Suspicions are usually raised from glucose detected on urine testing, which lead to further investigation. Fasting blood glucose levels are raised and HbA1c, which represents longer-term diabetic control, is also above the recommended values. The key feature that distinguishes Type 2 diabetes from MODY is that of insulin resistance, which is identified from high plasma insulin levels and/or the presence of acanthosis nigricans (Shaw, 2001).

Risk factors for development of Type 2 diabetes in children are listed in Box 1.

Additional obesity-related health problems
In adult life, the role of obesity in the pathogenesis of a number of potentially fatal conditions has been widely researched. It is now regarded as an established risk factor for several chronic diseases, and is hence a burden on health and economic resources, and an indicator for morbidity and mortality. The following problems highlight the need to tackle obesity in adolescence.

Hypertension Studies in the USA have shown that the risk of hypertension for moderately obese men is roughly two-fold higher than for their non-obese peers (Thompson et al, 1999). The relationship between obesity and hypertension has been extensively researched, and the amount by which blood pressure rises is directly correlated to the degree of weight gain (Kannel et al, 1967). The Framingham study reported that, in males, for every 10% increase in relative weight, blood pressure increased by 6.5mmHg. A 15% increase was associated with an 18% increase in systolic pressure. What is perhaps most worrying is the fact that young obese adults appear to be at no less risk. Data from the USA has indicated that overweight adults aged 20-44 years of age have a 5.6 times greater risk of developing this problem (Burton et al, 1985).

Coronary heart disease A large-scale study of women aged 30-55 years of age observed the incidence of non-fatal and fatal coronary events in relation to weight gain during an eight-year period (Manson et al, 1990). During the study, 605 new events were reported, 83 of which were fatal, with a higher body mass index confirmed as having a positive association with each category of coronary heart disease. Most worrying is the indication that in women in the heaviest categories (that is 30% or more above their recommended weight) 70% of events in this group were directly attributable to their excess weight (Manson et al, 1990).

Hyperlipidaemia The risk of abnormal lipid levels in obese subjects increases across the spectrum of body mass indices, although the effect of obesity on lipid levels is less than its effect on hypertension (Thompson et al, 1999). Many subjects are unaware that they have a problem and are often detected on random screening. A recent study indicated that high blood cholesterol was evident in the obese of both sexes (Must et al, 1999).

Osteoarthritis Excessive body mass places an additional strain on weight-bearing joints and is a further cause for poor morbidity and reduced quality of life.

Related obesity problems The incidence of gallstones, cancer (particularly colon cancer) and stroke are increased in the overweight in both sexes with this risk increasing in line with the degree of obesity (Field et al, 2001).

Treatment and management of young people
Initial treatment mimics that offered to adults who develop diabetes, with weight loss, dietary advice and increased activity levels forming the basis of their management. Initial evaluation should also include assessment for associated morbidity, including cardiac risk factors, joint problems and psychiatric disturbances (Williams et al, 1997), which may require separate investigation and treatment.

It may be possible for some cases to be managed in the primary care setting with a multidisciplinary approach involving GP, practice nurse, school nurse or health visitor and dietitian. Where there are additional health risks, however, referral to specialist services (such as a paediatrician) may need to be considered. For those who have evidence of Type 2 diabetes, referral to a diabetologist would be a vital component of management.

The failure of lifestyle advice to normalise blood glucose values signals the need to commence oral therapy. Metformin has been cited as the drug of choice in the hope that it will lead to weight loss and help insulin resistance (Bailey and Turner, 1996).

Dietary management
Referral to a dietitian is required to enable evaluation and alterations to dietary intake that can be made for the whole family. This will reinforce the importance of healthy eating and remove the focus from the child. Food diaries are useful, and can provide information for professionals who can use the content to help the family adapt to a more nutritionally balanced diet.

Exercise
Increasing the level of physical activity is an integral part of any weight-loss programme and does not need to involve participation in rigorous sports to be effective. A brisk daily walk lasting 20 minutes or longer is generally advocated, but it is sensible to start gradually and increase slowly.

Behaviour modification
Tackling obesity is a major challenge and there are many problems associated with encouraging children to adopt the behaviour modification recommended to them. Many of these children find it difficult to achieve and maintain the significant degree of weight loss required (Ng and Burren, 2000) and intervention will need to involve parents and other siblings, particularly in those families where other members are also obese. Compliance with lifestyle advice is also seen to be difficult, particularly because the majority of these children do not feel unwell and therefore do not perceive themselves as ill (Ehtisham et al, 2000).

For these reasons behaviour modification needs to address the wider issues, educating the family to remove stimuli from their daily living environment that perpetuate the obese state. Such strategies could include limiting the amount of fattening foods in the house, eating all meals at the dinner table, eliminating snacks between meals and not providing second helpings (Moran, 1999).

Conclusion
The health implications from earlier onset of diabetes are enormous, with very real concerns for the risk of earlier development of complications and rising levels of morbidity and mortality as these children progress into adulthood.

There are also economic implications with predicted rises in the cost of caring for people with diabetes in years to come.

Ng and Burren (2000) suggest that the diagnosis of Type 2 diabetes needs to be considered in all obese children or adolescents, particularly those who exhibit signs of hyperinsulinaemia, those from high-risk ethnic minority groups and those with a strong family history. The challenge for nurses lies in the early recognition and tackling of obesity, which precedes the onset of the diabetes. An increased awareness of the problems of childhood obesity offers nurses the opportunity to implement interventions that, it is hoped, will reduce the long-term health problems associated with diabetes in this younger client group.

American Diabetes Association. (2000) Type 2 diabetes in children and adolescents. Diabetes Care 23: 381-389.

Bailey, C.J., Turner, R.C. (1996) Metformin. New England Journal of Medicine 334: 9, 574-579.

Burton, B.T., Foster, W.R., Hirsch, J., Itallie, T.B. (1985) Health implications of obesity: an NIH Consensus Development Conference. International Journal of Obesity 9: 155-170.

Ehtisham, S., Barrett, T.G., Shaw, N.J. (2000) Type 2 diabetes in UK children: an emerging problem. Diabetic Medicine 17: 867-871.

Field, A.E., Coakley, E.H., Mudst, A. et al. (2001) Impact of overweight on the risk of developing common chronic diseases during a ten-year period. Archives of General Psychiatry 161: 13, 1581-1586.

Fruhbeck, G. (2000) Childhood obesity: time for action, not complacency. British Medical Journal 320: 328-329.

Hattersley, A.T., Beards, F., Ballantyne, E. et al. (1998) Mutations in the glucokinase gene of the fetus result in reduced birth weight. Nature Genetics 19: 268-270.

Hope, R.A., Longmore, J.M., Hodgetts, T.J., Ramrakha, P.S. (1994) Oxford Handbook of Clinical Medicine. Oxford: Oxford University Press.

Kannel, W.B., Brand, N., Skinner, J.J. Jnr, et al. (1967) The relationship of adiposity to blood pressure and development of hypertension: the Framingham study. Annals of Internal Medicine 67: 48-59.

Manson, J.E., Colditz, G.A., Stamfer, M.J. et al. (1990) A prospective study of obesity and risk of coronary heart disease in women. New England. Journal of Medicine 322: 13, 882-889.

Moran, R. (1999) Evaluation and treatment of childhood obesity. American Family Physician 59: 859-873.

Must, A., Spadano, J., Coakley, E.H. et al. (1999) The disease burden associated with overweight and obesity. Journal of the American Medical Association 282: 16, 1523-1529.

National Audit Office. (2001) Tackling Obesity in England. London: NAO.

Ng, G.Y.T., Burren, CP. (2000) Type 2 diabetes in adolescence: unearthed at the time of registration with the general practitioner. Practical Diabetes International 17: 8, 273-274.

Pinhas-Hamiel, O. (2001) Type 2 diabetes: not just for grown-ups anymore. Contemporary Paediatrics 18: 1, 102.

Shaw, N.J. (2001) Non-insulin dependent diabetes in children: a commentary. Practical Diabetes International 18: 1, 3.

Thompson, D., Edelsberg, J., Colditz, G.A. et al. (1999) Lifetime health and economic consequences of obesity. Archives of Internal Medicine 159: 2177-2183.

Williams, C.L., Campanaro, L.A., Squillace, M., Bollella, M. (1997) Management of childhood obesity in paediatric practice. Annals of the New York Academy of Science 817: 225-240.