Increased bone turnover during the third trimester of pregnancyand decreased bone mineral density after parturition in adolescentsas compared to age-matched control patients

Abstract

To evaluate the impact of pregnancy on bone, we studied bone turnover at the first (T1) and third (T3) trimester of gestation in 58 adolescents and 28 healthy adolescents who had never been pregnant. Total body (TB) and lumbar spine (LS) bone mineral density (BMD) and body composition were evaluated by dual-energy X-ray absorptiometry in all control patients (C) and after parturition in 28 pregnant patients (G). Paired and unpaired t tests, Mann-Whitney and Pearson correlation tests were used. Bone turnover markers were above the reference range for adult women in more than 80% of the adolescents, with no difference between C and G patients at T1. Increase in urinary N-telopeptide crosslinks of type I collagen and serum bone-specific alkaline phosphatase, markers of bone turnover, was seen during pregnancy ( p < 0.0001). Body composition did not differ between groups, but LS BMD, percentage of expected LS BMD, LS Z-score, percentage of expected TB BMD and TB Z-score were lower in G than C patients ( p < 0.05). TB BMD was positively correlated with LS BMD (r2 = 0.52). The inverse correlations between bone markers and LS BMD suggest that the increased bone turnover during pregnancy probably explains the low bone density after parturition. The impact on future peak bone mass must be studied.

Bone mineral density in people living with HIV: a narrative review of the literature

“…Results from a more recent study are in accordance with the important role of body composition and have indicated that weight, BMI, and body fat were all associated with BMD, especially in females [ 192 ], which also highlights the importance of nutrition on BMD, especially because low calcium and vitamin D intake reduces BMD [ 193 ]. A study in Brazil indicated that HIV-positive populations have calcium and vitamin D deficiencies, even though their dietary intake is similar to that described in other young Brazilian populations [ 194 , 195 ]. Limitations in studies regarding nutrition and BMD are often due to the fact that participants need to recall what they have consumed and errors might slip in as it is self-reported.…”

Factors associated with low bone mineral density in a Brazilian cohort of vertically HIV-infected adolescents

“…8 We found a high prevalence of low BMD among vertically HIV-infected adolescents, as almost a third of the patients had a low BMD Z-score at LS and/or TB. In 28 normal female adolescents of similar age range, ethnicity, social conditions, and nutritional status we previously identified that only two had BMD Z-scores at or below À2 SD, 14 which is very different from the prevalence of low BMD in these HIV-infected patients. Different criteria are applied in studies with young seropositive patients, which make it difficult to compare these with our findings.…”

“…38 We detected important inadequacies in the intake of bone health-related nutrients in the adolescent HIV population, although calcium and vitamin D intake were similar to that described in other young Brazilian populations. 14,39 Overall nutritional status had a positive influence on bone and this might explain the trend for higher BMD in those patients with undetectable viral load, who also had a better diet in relation to energy, carbohydrate, and calcium. Dietary intake was determined by a single 24-h recall, so these values are only an estimate.…”

Office practice of osteoporosis evaluation

“…In anorexia nervosa, hypogonadism and nutrition related factors are critical (11). Pregnancy and lactation usually lead to a transitory decrease in bone density in adult women, but it remains unclear if adolescents also recover from pregnancy-induced bone loss or if they will have limited peak bone mass and will be at a higher risk for osteoporosis later in life (42).…”