ABSTRACT. Clinical and laboratory endocrine variables in 29 adult institutionalized patients with Down's syndrome were compared with those of matched controls consisting of other mentally retarded patients from the same institution. Of the clinical variables, testes volume and body height were significantly lower in patients with Down's syndrome than in control patients. The thyroid function tests documented a higher average TSH level in Down's syndrome than in other mentally retarded patients. However, there was no clear‐cut correlation between TSH and thyroid hormone levels. The data indicate that there is a tendency towards primary thyroid dysfunction in Down's syndrome. In addition, there is some evidence indicating a relative failure of TSH secretion. In male patients, estradiol was elevated compared to controls. FSH and LH also seemed slightly higher in the study group, but the differences only reached statistical significance when patients on chronic medication were omitted. Prolactin was significantly greater in the Down's syndrome patients than in the controls, both over the entire sample and in the subgroup of men with Down's syndrome, with P‐values of around 0.001. The elevation of prolactin was not due to medication and did not correlate to thyroid function or difficulties during blood sampling. In females, the difference was not statistically significant. Laboratory tests that may be associated with endocrine disease or might indicate disease which could influence the endocrine status, were also included in this study. Compared with the controls, ESR, creatinine and uric acid levels were higher in Down's syndrome patients, while albumin was lower, all with P‐values lower than 0.001. Vitamin B12 was moderately lower in Down's syndrome patients than in controls (P<0.05).

ABSTRACT. In a Norwegian institution for the mentally retarded, 29 adults with chromosomally verified Down's syndrome were compared to other mentally retarded patients with respect to serum somatomedin C (SmC) (insulin‐like growth factor 1 [IGF‐1]). Contrary to what has been observed in children, no shortage of SmC could be demonstrated in the adults with Down's syndrome. The results were within the normal range, and there was no difference between those with Down's syndrome and the other mentally retarded patients. Human growth hormone (HGH) and body height were studied in a previous work. Some correlations with these data are, nevertheless, included herein because they are of relevance. SmC correlated with body height in Down's syndrome, while there was no correlation between SmC and HGH or between HGH and body height.