Bone fragility seen in older men, women with hypoparathyroidism
About 1 in 3 postmenopausal women, 1 in 5 men showed osteoporosis signs
Postmenopausal women and men over age 50 with chronic hypoparathyroidism showed signs of significant bone fragility, with a high proportion of fractures and osteoporosis, according to a study that calls for a closer follow-up of patients’ skeletal health.
The study, “Skeletal health status among patients with chronic hypoparathyroidism: results from the Canadian National Hypoparathyroidism Registry (CNHR),” was published in Osteoporosis International.
Hypoparathyroidism, which is marked by low parathyroid hormone (PTH), is most often caused by surgery that damages the neck’s parathyroid glands, or their blood supply. The condition’s nonsurgical causes are frequently autoimmune, congenital, familial, or unknown.
A lack of PTH leads to decreased calcium, resulting in lower bone turnover, or the continuous process of bone tissue being broken down and rebuilt. The condition has been linked with abnormalities in bone density, structure, and strength.
Regular skeletal health follow-up in chronic hypoparathyroidism isn’t explicitly recommended under current international guidelines, and there’s limited information about skeletal health and the effects of treatment on all ages, especially postmenopausal women at increased risk of bone fragility.
Using data from the Canadian National Hypoparathyroidism Registry (CNHR), scientists based mostly in Canada assessed the skeletal health of adults with chronic hypoparathyroidism, focusing on postmenopausal women, who represent a large proportion of the registry’s population. The work was funded in part by Amolyt Pharma.
Assessing skeletal health in older hypoparathyroidism patients
In total, 101 adults with chronic hypoparathyroidism were assessed, of whom 83 (82%) were women. Thirty-five women (42%) were premenopausal and 48 (58%) were postmenopausal. The patients were receiving conventional therapy, such as calcium supplements and active vitamin D, with or without PTH replacement therapy with teriparatide, PTH (1-34), a fragment of human PTH.
Tingling sensations were the most common symptoms (44.6%), followed by numbness (39.6%), muscle cramps (33.7%), and fatigue and muscle spasms (16.8%). Less frequent symptoms included confusion (10%), seizure (9%), and depression (3%).
Compared with premenopausal women, postmenopausal women had significantly higher calcium, alkaline phosphatase, a marker for bone and liver health, and 25-hydroxyvitamin D, the primary form of vitamin D in blood. They also had significantly lower eGFR, a marker for kidney function, and thyroid-stimulating hormone, which helps regulate metabolism.
Bone mineral density (BMD), as assessed with noninvasive dual-energy X-ray absorptiometry (DXA), was significantly lower in postmenopausal women in the hip, lower spine, and the femoral neck at the top of the leg bone. Among postmenopausal women, nearly half (44%) had normal BMD, while 1 in 4 (25%) had low BMD. BMD was also significantly lower in women than men in the hip, femoral neck, and 1/3 radius, which refers to the bone at the middle third of the arm bone.
Patient fragility fractures
Of the 12 patients with a reported history of fragility fractures, most (83.3%) were postmenopausal women, while two were men at least 50 years of age. A fragility fracture is a type bone fracture from a low-impact trauma that wouldn’t typically occur in a healthy bone. The prevalence of fragility fractures was similar between postmenopausal women and men 50 or older (20.8% vs. 22.2%). No fragility fractures were reported in premenopausal women or men younger than 50.
About 1 in 3 postmenopausal women (31.3%) and 1 in 5 men at least 50 years old showed signs of osteoporosis, that is, brittle and weak bones. None of the men under age 50 had osteoporosis.
In a statistical analysis, longer disease duration was associated with higher BMD in the lower spine, femoral neck, and total hip.
Most patients treated with PTH (1-34) were postmenopausal women (80%). Although there were no significant BMD differences in the lower spine between PTH (1-34) users and those solely on conventional therapy, BMD values in the femoral neck, total hip, and 1/3 radius were lower in PTH (1-34) users compared with non-PTH users. Lastly, no significant differences in blood calcium were observed with or without PTH (1-34) therapy.
“Data from this prospective cohort study demonstrated significant bone fragility in postmenopausal women with chronic [hypoparathyroidism],” the scientists wrote. “Similarly, a large percentage of men over the age of 50 years had osteoporosis by BMD criteria or prior fragility fracture. Our study strongly suggests that a systematic timely evaluation of skeletal health by DXA assessment and spinal imaging would be useful to better assess fracture risk and bone strength in chronic [hypoparathyroidism].”
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