Objective To test the hypothesis that very low birth weight (VLBW, <1500 g) is associated with impaired skeletal health in adulthood.
Methods We evaluated skeletal health at age 18.5 to 27.1 years in 144 subjects with VLBW and 139 born at term. The term born were matched for sex, age, and birth hospital. Those with VLBW were born at 29.2 weeks of gestational age with a mean birth weight of 1126 g and a birth weight z score of −1.2. Calcium and vitamin D intake and physical activity were assessed with a questionnaire and areal bone mineral density (aBMD) by dual energy x-ray absorptiometry (Hologic Discovery A).
Results The VLBW subjects had 2.4-fold odds (95% CI, 1.5 to 4.1, height-adjusted OR 1.8 [1.1 to 3.2]) of having a lumbar spine aBMD z score within the osteopenic or osteoporotic range. The VLBW adults also had a 0.56-unit (0.34 to 0.78) lower femoral neck z score for aBMD, with the difference remaining statistically significant after adjustment for height, exercise intensity, and intake of calcium and vitamin D.
Conclusions Previous studies show that VLBW infants have compromised bone mass accrual during childhood. Our data show that VLBW subjects studied in adulthood, close to the age of peak bone mass, have significantly lower bone mineral density than do their peers born at term. This indicates that compromised childhood bone mass accrual in preterm children translates into increased risk for osteoporosis at adult age. Our findings suggest vigilance in osteoporosis prevention in those with VLBW.