Does birth weight predict adult weight?

Nutrition Research Newsletter, August, 2004

Learning more about the factors leading to obesity is extremely important. It has been suggested that prenatal environment, maternal factors, and birth weight may have lifelong consequences for obesity. BMI is frequently used as a marker of adult obesity and is correlated with direct measures of adiposity in children and younger adults. However, BMI may not be the best method to measure obesity during childhood and older adulthood, as it neglects the proportions of fat, muscle, bone and organ mass. Studies that examined the relation between birth weight and more direct measures of adiposity are less consistent than when BMI is used.

Researchers explored these associations further by measuring anthropometric variables and body composition in a group of men aged 59-70 years who had information on both prenatal and infant growth and participated in the Hertfordshire Cohort Study. From 1911 to 1948, midwives collected detailed records, including information on birth weight and weight at 1 year of age, on infants born in the county of Hertfordshire, UK. Men who were born between 1931 and 1939 and were still living in East Hertfordshire were traced with the aid of the National Health Service central registry. Subjects agreeing to participate in a follow-up home interview included 768 men. Trained nurses collected medical and social history. Anthropometric measurements included measurements of height, sitting height, weight, and waist, hip, midupper arm, and mid-thigh circumferences. Skinfold thicknesses were measured at the triceps, biceps, subscapular, and suprailiac sites and grip strength was measured.

Birth weight was significantly and consistently positively associated with adult BMI and fat-free mass but not with measures of adult fat mass. In contrast, weight at 1 year of age was associated with adult BMI, fat-free mass, and fat mass.

Although consistently reported, the positive relation between birth weight and adult BMI may reflect prenatal and maternal influences on fat-free mass rather than on fat mass in older individuals. The postnatal environment may be more influential than prenatal factors in the development of obesity later on in life.

A. Sayer, H. Syddall, E. Dennison, et al. Birth weight, weight at 1 y of age, and body composition in older men: finds from the Hertfordshire Cohort Study. Am J Clin Nutr;80:199-203 (July, 2004). [Correspondence: AAihie Sayer, MRC Environmental Epidemiology Unit, University of Southampton, Southampton SO 16 6YD, United Kingdom. E-mail: aas@mrc.soton.ac.uk].