Osteoporosis in men with hypogonadism because of ApoA-I Leu75Pro amyloidosis under long-term testosterone therapy

Apo A-I Leu75Pro amyloidosis is a rare systemic hereditary disease, whose hallmark and earliest involvement is testicular impairment, characterized by hypogonadism and macrorchidism; renal and hepatic involvement are the other characteristics.

To evaluate for the first time the prevalence of osteopenia, osteoporosis and vertebral fractures (VFs) in men with this form of amyloidosis affected by hypogonadism and under long-term testosterone replacement therapy (TRT).

Retrospective study on 50 men >50 years (median age 64.5) with dual-energy X-ray absorptiometry (DXA), hormonal, and biochemical data available at least 3 years after the start of TRT. Serum gonadal hormones and bone markers, lumbar and femoral DXA-scan with morphometric assay for evaluation of VFs were assessed.

At 7.5 years from start of TRT, lumbar and/or femoral osteopenia and osteoporosis were found in 54% and 10% of patients, respectively. Of the men who had the morphometric assay performed, five of 34 (14.7%) had VFs. Compared to patients with normal bone mineral density, men with osteopenia and osteoporosis were older, had lower body mass index, higher sex hormone binding globulin and showed more frequently renal involvement. Multiorgan involvement, without different TRT dosage, was associated with lower testosterone levels.

Men with hypogonadism because of Apo A-I Leu75Pro amyloidosis under long-term TRT had a high burden of low bone mass (64%) and VFs (almost 15%). Osteopenia-osteoporosis was more frequently observed in older patients with multi-organ disease, which might contribute to impair bone health beyond hypogonadism.