Sex steroids and body composition in men with cystic fibrosis

Abstract

Objective: Delayed sexual maturation and low body weight is common in cystic fibrosis (CF). Concomitant data on sex hormones and concomitant body composition are lacking in men with CF. Design: Cross-sectional study. Subjects and methods: Serum levels of testosterone, 17b-oestradiol (E 2 ), 25-hydroxyvitamin D (25(OH)D), sex hormone-binding globulin (SHBG) and LH were measured by RIA and total and regional lean body mass (LBM), fat body mass (FBM), bone mineral content and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry, in men with CF (n ¼ 40; age 24:7^5:4 years) and age-matched healthy controls ðn ¼ 28; age 25:7^3:7Þ: Only men without acute disease exacerbation or systemic glucocorticoid treatment were included. Results: Mean levels of hormonal serum parameters differed significantly between healthy controls ðtestosterone ¼ 20:2^5:5 nmol=l; E 2 ¼ 95:0^20:2 pmol=l; 25ðOHÞD ¼ 62:8^28:3 nmol=lÞ and patients ðtestosterone ¼ 15:9^4:1 nmol=l; E 2 ¼ 60:7^19:4 pmol=l; 25ðOHÞD ¼ 39:5^17:8 nmol=l; P , 0:001Þ while no difference was found for SHBG or LH. Eleven (for E 2 , 19 of 40, for 25(OH)D, 20 of 40) out of 40 patients had serum testosterone levels 2 S.D. below the mean of normal. Men with CF showed a relative shift from FBM to LBM and a different body fat distribution compared with healthy controls ðP , 0:01Þ: Testosterone was not correlated with weight, total or regional LBM or FBM, but significantly with BMD ðr ¼ 0:32; P , 0:05Þ independently from body height and 25(OH)D levels. E 2 was correlated with regional and total FBM ðr ¼ 0:48; P , 0:05Þ: In a multiple regression analysis of the joint effect of testosterone and body components on E 2 , a testosteroneindependent effect was found for FBM. Conclusions: CF patients with stable disease have moderately reduced serum testosterone levels. This might already imply detrimental effects on bone. The change in LBM of patients appears to have no direct association with sex hormone levels while low FBM might cause reduced net conversion of serum testosterone to E 2 with possible effects on FBM distribution.

The effect of vitamin K supplementation on biochemical markers of bone formation in children and adolescents with cystic fibrosis

“…Similar findings have also been reported by other authors [8,10,13,18,19] .These results suggest that the minimum recommended dose of vitamin D supplementation for CF patients [3] may not be adequate even in Greece where solar exposure is high. Although no correlation between serum 25(OH)D levels and BMD zscores was found, we observed a weak, nevertheless positive, correlation between serum 25(OH)D levels and biochemical markers of osteoblastic activity (Gla-OC, PINP, PICP) in our patients.…”

Failure of High-Dose Ergocalciferol to Correct Vitamin D Deficiency in Adults with Cystic Fibrosis

“…One of these issues is bone health, because studies using dual-energy x-ray absorptiometry measurements of bone density have determined that, despite their young age, approximately 20 to 25% of adults with CF have osteoporosis and another 40% have osteopenia (3)(4)(5). The etiology of this bone disease is multifactorial, with contributors including fat malabsorption (resulting in vitamin D malabsorption and abnormal calcium metabolism) (6)(7)(8), glucocorticoid therapy (9, 10), poor nutritional status (11), inadequate gonadal hormones (10,12), and elevated circulating cytokines (13). Recognition of this increased risk of osteoporosis in CF has led to greater efforts to optimize vitamin D status and calcium absorption (4,14).…”

Cystic fibrosis-related bone disease

“…Regarding the sex hormones, hypogonadism is well associated with decreased bone density. Although this contribution to CFBD has not been formally entrenched, both men and women with CF have a significant risk of hypogonadism (28, 29). This finding has however been associated with an increase in vertebral fractures in CF (30).…”