Short stature in man may result from a deficiency of GH or insulin-like growth factors (IGFs). In African pygmies and other individuals with the pygmy trait, serum GH and IGF-II are similar to levels in taller subjects, but serum IGF-I levels are low. To determine whether another population with comparably short stature has similar or related defects, we studied the Mountain Ok population of Papua New Guinea. The mean height of adult men was 152 +/- 6.0 (+/- SD) cm (n = 141), and that of women was 146 +/- 5.7 cm (n = 150). Serum GH and IGF-II concentrations were in the normal (U.S.) range in the Mountain Ok subjects. In the men, serum IGF-I values were also normal, thereby distinguishing the endocrine profile associated with short stature in these subjects from that in African pygmies. Serum IGF-I was not measured in any Mountain Ok women. Since marginal dietary protein is characteristic of the traditional Papua New Guinea diet, we determined serum albumin and prealbumin concentrations in the Mountain Ok subjects. The serum proteins were in the normal (U.S.) range (30-50 g/L for albumin; 10-40 mg/dL for prealbumin), indicating that chronic or acute malnutrition was unlikely in these subjects. Taken together, these findings indicate that short stature in the Mountain Ok people of Papua New Guinea is associated with normal serum GH, IGF-I, IGF-II, and protein levels and indicate that other factors determine stature in some populations with short stature.

Two circulating GH-binding proteins (GH-BP), one of which is related to the GH receptor, have been described. To assess their possible role in or link with determining statural growth, we measured their activity/level in the serum of 25 adult subjects from a short-statured population from the highlands of Papua New Guinea (Mountain Ok people, similar in stature to African pygmies) and in 25 normal-statured North American control subjects. The Mountain Ok people have normal levels of GH, insulin-like growth factor-I (IGF-I), IGF-II, and serum albumin and prealbumin in association with short stature, making them a unique study population. Levels of the high affinity (GH receptor-related) GH-BP were significantly lower in the Mountain Ok subjects than in the taller controls (5.2 +/- 3.0% vs. 10.6 +/- 3.9% GH bound/160 microL, respectively; mean +/- SD; P less than 0.001). In contrast, the low affinity GH-BP was comparable in Mountain Ok and control subjects. Because of the structural similarity between the GH receptor and GH-BP, these data suggest that a limitation in GH receptor/GH-BP endowment may be associated with short stature despite normal circulating IGF-I levels. Alternatively, it is possible that the GH-BP itself plays an important role in growth promotion. Thus, the GH receptor (and/or GH-BP) complement may be a determinant of the genetically programmed height achieved.

Context: The Mountain Ok (Mt Ok) people of Telefomin, who live at the interior of Papua New Guinea (PNG), were documented over 25 years ago to be one of the shortest populations on record, with average adult height below the fifth percentile (US). Serum Growth Hormone was detectable, Insulin-like Growth Factor-1 and serum indicators of protein nutritional status fell within the normal range, suggesting that these were not primary factors for their relative short stature.Objective: Since the Telefolmin people have experienced recent socioeconomic changes, they were re-evaluated in 2008, to examine height, weight, and body mass index (BMI), for insight into relative contributions of environment and other factors that modulate stature in children and adults.Study Design and Setting: Cross-sectional anthropometric data were collected from 474 individuals at Telefomin in 2008, and compared with anthropometric data from 342 individuals measured in 1983.

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