Bone mineral density of the spine and femur in healthy Saudi females: relation to vitamin D status, pregnancy, and lactation

Bone mineral density (BMD) measurements of the anterio-posterior lumbar spine and the proximal femur using dual-energy x-ray absorptiometry, as well as relevant clinical and biochemical parameters, were determined in 321 healthy Saudi females in order to establish reference values and to study the effects of physical and lifestyle factors on BMD. Mean +/- SD of age, body mass index (BMI), number of pregnancies, and total duration of lactation were 35.4 +/- 11.3 years, 26.5 +/- 5.2 kg/m2, 3.1 +/- 3.1, and 23.7 +/- 42.4 months, respectively. Mean +/- SD of serum calcium, 25-hydroxyvitamin D (25OHD), and PTH levels were 2.37 +/- 0.09 mmol/liter, 24.5 +/- 17.2 nmol/liter, and 52.0 +/- 30.8 pg/ml, respectively. Peak BMD values were observed around age 35 years at the spine and earlier at the femur. Compared with USA females, Saudi females had lower weight-matched Z scores at the spine (-0.126 +/- 1. 078, P = 0.04), femoral neck (-0.234 +/- 0.846, P < 0.0001), and Ward's triangle (-0.269 +/- 1.015, P < 0.0001). Further, the prevalence of osteopenia and osteoporosis in subjects >/=31 years old were 18-41% and 0-7%, respectively, depending on the site examined. Severe hypovitaminosis D (25OHD level </=20 nmol/liter) was present in 52% of the subjects. However, there was no correlation between 25OHD level and BMD at any site. Parathyroid hormone (PTH) levels correlated significantly with 25OHD levels (r = -0.28, P < 0.0001) and with weight-matched BMD Z scores at the spine (r = -0.17, P = 0.005), femoral neck (r = -0.16, P = 0.007), and Ward's triangle (r = -0.2, P = 0.0008), suggesting that the distribution of 25OHD levels in the cohort is below the threshold needed for maintaining normal BMD. On the other hand, number of pregnancies and total duration of lactation correlated with weight-matched BMD Z scores at the spine (r = -0.17, P = 0.003; r = -0.1, P = 0.08, respectively). We conclude that BMD in healthy Saudi females is significantly lower than in their USA counterparts. This may be due in part to increased number of pregnancies and longer duration of lactation together with prevalent vitamin D deficiency. http://link.springer-ny.com/link/service/journals/00223/bibs /65n1p23. html

Primary hypothyroidism-associated TSH-secreting pituitary adenoma/hyperplasia presenting as a bleeding nasal mass and extremely elevated TSH level

A 41-year-old male with primary hypothyroidism and a huge TSH-secreting pituitary tumor presented with a bleeding nasal mass that was initially misdiagnosed as a paraganglioma. Other unique features of the case include lack of complaints related to hypothyroidism, an extremely elevated TSH level of 3474 mU/l, and a low prolactin level. The presence of primary hypothyroidism made differentiating TSH-secreting pituitary adenoma from secondary thyrotroph hyperplasia difficult. A low molar ratio of alpha-subunit to TSH on presentation, together with normalization of TSH level and a 50% reduction in the size of the tumor after 6 weeks of thyroxine replacement therapy, suggested the presence of thyrotroph hyperplasia. However, the lack of further decrease in the size of the tumor that was associated with increased metabolic activity on 18-FDG PET scan, intense uptake on octreotide scan, and an elevated alpha-subunit to TSH molar ratio despite the normalization of free T4 and TSH levels for 16 months suggested the coexistence of thyrotroph adenoma. Together, the findings support the view that thyrotroph adenoma/irreversible hyperplasia can result from long standing primary hypothyroidism.