ERN BOND

CONTEXT: Prader-Willi syndrome (PWS) is a rare complex genetic syndrome, characterized by delayed psychomotor development, hypotonia, and hyperphagia. Hormone deficiencies such as hypogonadism, hypothyroidism, and growth hormone deficiency are common. The combination of hypotonia, low physical activity, and hypogonadism might lead to a decrease in bone mass and increase in fracture risk. Moreover, one would expect an increased risk of scoliosis due to hypotonia and low physical activity. OBJECTIVE: To study the prevalence and risk factors for skeletal problems (reduced bone mineral density, fractures, and scoliosis) in adults with PWS. METHODS: We retrospectively collected patient characteristics, medical history, medication, biochemical measurements, dual-energy X-ray absorptiometry scans, and spinal X-rays and reviewed the current literature. RESULTS: We included 354 adults with PWS (median age 31 years; 43% males), of whom 51 (14%) had osteoporosis (T-score below -2.5) and 143 (54%) had osteopenia (T-score -1 to -2.5). The most prevalent modifiable risk factors for osteoporosis were hypogonadism, insufficient dairy intake, sedentary lifestyle, and corticosteroid use. Male sex was associated with osteoporosis (P = .005). Growth hormone treatment was not associated with osteoporosis. A history of vertebral fractures was present in 10 (3%) and nonvertebral fractures in 59 (17%). Scoliosis was present in 263 (80%), but no modifiable risk factors were identified. CONCLUSION: Besides scoliosis, osteoporosis is common in adults with PWS. Based on the literature and the risk factors for osteoporosis found in our cohort, we provide practical clinical recommendations to avoid skeletal complications in these vulnerable patients.

Like Lejeune and associates, 1 we have found an association between low environmental temperature and the risk of subarachnoid hemorrhage. 2 In our study, which was carried out in King County, Wash, the meteorologic variable with the strongest relation was dew point. Dew point is the temperature to which a given parcel of air must be cooled at a constant pressure and constant water vapor content for saturation to occur. We hypothesize that exposure to cold was the actual risk factor, probably because of changes in blood pressure, but that people were more likely to expose themselves to low temperatures on clear days when the dew point was low than on rainy or overcast days when the temperature was the same but the dew point was higher. Thus, low dew point would be associated more strongly than temperature alone with an increased risk of subarachnoid hemorrhage. We wonder whether the investigators from France also found an association of subarachnoid hemorrhage with dew point.