The effect of delayed puberty on peak bone mineral density in men is unknown. To determine whether such a delay reduces normal peak bone density and leads to osteopenia during adulthood, we measured radial bone mineral density by single-photon absorptiometry and spinal bone mineral density by dual-energy x-ray absorptiometry in 23 men who had a history of constitutionally delayed puberty and 21 men who underwent normal puberty. Their mean ages were 26 and 24 years, respectively. The groups were matched for other factors known to affect bone mass.

The mean (±SD) radial bone mineral density was significantly lower in the men with a history of delayed puberty than in the normal men (0.73±0.07 vs. 0.80±0.05 g per square centimeter; P<0.0002). Spinal bone mineral density was also significantly lower in the men with delayed puberty than in the normal men (1.03±0.10 vs. 1.13±0.11 g per square centimeter; P<0.003). Radial bone density was at least 1 SD below the mean value for the normal men in 15 of the 23 men with a history of delayed puberty, and spinal bone density was similarly decreased in 10 of the 23.

Adult men with a history of constitutionally delayed puberty have decreased radial and spinal bone mineral density. These findings suggest that the timing of puberty is an important determinant of peak bone density in men. Because the peak bone mineral density achieved during young adulthood is a major determinant of bone density in later life, men in whom puberty was delayed may be at increased risk for osteoporotic fractures when they are older. (N Engl J Med 1992;326: 600–4.)