Studies on Fat in Youth Show That Risks Emerge Early, and Are Hard to Reverse

Childhood obesity is more than a “problem,” it’s an indicator that what’s gone wrong metabolically has set young people up for a host of health problems later on. What’s worse, once a child becomes overweight, it can be very hard to reverse either the weight gain or its effects.

Studies presented at Sunday morning’s session, “Fitness and Fatness in Youth With or At Risk of Diabetes,” revealed how much researchers are learning about the effects of excess weight in children and teenagers, right down to the cellular level.

The sessions reflected a larger message at the 74^th Scientific Sessions of the American Diabetes Association, which conclude Tuesday in San Francisco, California: children are not “little adults.” Their bodies react differently to risk factors, and this reality must be taken into account when developing treatment for obesity and diabetes mellitus, both type 1 (T1DM) and type 2 (T2DM). Obesity’s rise, both in the United States and around the world, is especially problematic for T1DM youth, as they must take insulin which puts them at further risk of weight gain. Among the studies presented:

• Antje Korner, MD, of the University of Leipzig, presented results that show the effects of obesity show up in fat tissue quite early. Tissue samples collected from 171 children, ages 2 years to 19 years, compared the composition of adipose tissue in both lean children and those who were overweight. This tissue contains adipocytes, which increase in size and number with age. But for obese children, both the size and number of adipocytes accelerated, which has important health implications.¹ The size and presence of adipocytes affects important hormones, including estrogen, and evidence that their production is accelerated in children carrying excess adipose tissue suggests these youth will experience endocrine problems earlier in life.

• Sara Michaliszyn, PhD, of Youngstown State University, explored beta cell function and incretin effects in obese youth, for whom data are limited.² Using the clamp method, she studied 255 obese youth and found evidence that damage to beta cell function occurs early, with implications for development of T2DM. In the study, 173 had normal glucose tolerance, 48 had impaired glucose tolerance (IGT) and 34 had progressed to T2DM. Compared with the youth with normal glucose tolerance, beta cell function was 30% lower in the youth with IGT and 65% lower in the T2DM youth. Dr Michaliszyn’s study also calculated incretin effect, and observed a 38% decline in those with IDGT or T2DM, although there was some evidence that the youth with IGT were compensating for this effect.²

• Two presentations focused on youth with T1DM. Sabine Hofer, of Medizinische Universität at Innsbruck, Austria, reported on the effects that rising obesity rates are having on the difficulty of controlling A1C levels in youth with T1DM,³ while Charu Baskaran, MD, of the Joslin Diabetes Center, tracked weight in T1DM youth and found that those overweight by age 10 years were more than 8 times higher to be overweight at age 18 years.⁴

An audience member observed that that many of the results had implications for the emotionally charged issue of encouraging weight loss in younger girls; the commenter said data show girls who are overweight in their teens are more likely to skip insulin.

A sign of hope came from Curtis Harrod, MPH, of the University of Colorado, whose study examined the relationship between physical activity during pregnancy and infant birth weight and neonatal composition. Harrod found that there was little relationship between activity in the first two trimesters and neonatal composition, but that increased activity in the final trimester was associated with lower levels of neonatal adiposity. Thus, encouraging mothers who are at-risk of having overweight children to exercise more during pregnancy could have positive effects on the child at birth, and later in life.⁵

References

1. Landgraf K, Rockstroh D, Wagner IV, et al. Obesity in children is associated with early alterations in adipose tissue biology. Diabetes 2014;63(suppl 1): Abstract 159-OR.
2. Michaliszyn S, Lee S, Bacha F, et al. B-cell function, incretin hormones, and incretin effect in obese youth along with span of glucose tolerance from normal to prediabetes to type 2 diabetes. Diabetes 2014;63(suppl 1): Abstract 160-OR.
3. Hofer S, Dubose SN, Hermann JM, et al. The obesity epidemic and its consequences in youth with type 1 diabetes in the U.S. T1D exchange and German/Austrian DPV. Diabetes. 2014;63(suppl 1): Abstract 161-OR.
4. Baskaran C, Dougher C, Telo G, et al. Weight status of youth with type 1 diabetes over time: impact of childhood weight and glycemic control. Diabetes. 2014;63(suppl 1): Abstract 162-OR.
5. Harrod C, Chasan-Taber, L, Reynolds RM, et al. Physical activity during pregnancy and neonatal fat mass: the Health Start Study. Diabetes. 2014;63(suppl 1): Abstract 157-OR.