Fat accumulation: key to diabetes risk

The amount of fat a person accumulates in relation to their body size as they grow into adulthood, not their birth size or their growth per se, influences their risk of developing type 2 diabetes. Low birth weight has been tied to an increased risk of type 2 diabetes, and some researchers have proposed that the acceleration in growth experienced by people who are born small but reach normal adult size has harmful effects on metabolism. It is still uncertain whether people who are born small but catch up later or those who remain small throughout their lifetimes are at greater risk of type 2 diabetes. To investigate, American researchers looked at insulin sensitivity in 136 young men and women, some of whom were born small for gestational age and remained short as adults; some who were born small but reached normal height in adulthood; some who were of normal size at birth but grew up to be short adults; and some who were born at normal size and were normal size as adults. It was found that fat mass in adulthood was the only measurement significantly related to insulin sensitivity. Reduced insulin sensitivity is a precursor to diabetes. After they used statistical techniques to control for age, sex and body size in adulthood, the group of men and women who were born small but caught up as adults had significantly lower insulin sensitivity than the control group. Based on the results, the researchers proposed a 'fat accumulation hypothesis,' which states that 'an increased accumulation of fat during childhood, independent of birth size, will result in reduced insulin sensitivity.' Growth acceleration in height and weight as such is not a problem as long as a normal amount of fat is accumulated. The findings imply that all individuals, regardless of their size at birth, should try to achieve or maintain a normal fat mass for their body size. Parents of all children, independent of birth size or growth during childhood, should be aware of the risk of fat accumulation in their children.