Low birth weight and later development of insulin resistance and biochemical/clinical features of polycystic ovary syndrome.

Reduced insulin sensitivity in adult life has been reported in subjects born at term small for gestational age (SGA) and in those born prematurely with very low birth weight (LBW) (<1,500 g). We assessed whether LBW (<2,500 g) young women, irrespective of whether they were born SGA or adequate for gestational age (premature AGA), exhibited a reduction in insulin sensitivity through a prospective historical design. The risk of developing biochemical and clinical features of polycystic ovary syndrome was also investigated. The study population included 35 LBW women (19 SGA [BW range, 1,000-2,400 g] and 16 premature AGA [BW range, 1,700-2,440 g]) aged 21.8 +/- 1.8 years and 35 term AGA controls, of similar age, recruited from a neonatal registry. All women underwent clinical, ultrasonographic, hormonal, and metabolic evaluations, including the composite insulin sensitivity index. Women under hormonal contraception (21.4%) were excluded from hormonal and metabolic analyses. Composite insulin sensitivity index was significantly lower in LBW women even when the 2 LBW subgroups, SGA and premature AGA, were analyzed separately (4.4 +/- 2.2 and 4.0 +/- 1.7, respectively) than in controls (6.9 +/- 4.4). The LBW women showed a significantly higher incidence proportion of irregular menses (14/35 [40%] vs 2/35 [5.7%]) and a significantly higher free androgen index (5.8 +/- 3.5 vs 3.9 +/- 3.2). They also showed a nonsignificantly higher proportion of hirsutism, acne, and polycystic ovaries. In conclusion, LBW (<2,500 g) young women, irrespective of whether they were SGA and premature AGA, exhibited a reduction in insulin sensitivity as compared with born at term AGA women. Furthermore, they exhibited an increased risk of developing clinical and biochemical features of polycystic ovary syndrome.

Retinol binding protein 4, low birth weight-related insulin resistance and hormonal contraception.

It has been recently reported that increased serum levels of retinol binding protein 4 (RBP4), a molecule secreted by adipocytes and liver, could be an early marker of insulin resistance (IR). We determined whether serum RBP4 was increased in low birth weight (LBW)-young women as a model of early-onset IR, through a historical prospective study. The study-population included 35 LBW and 35 born at term appropriate for gestational age (term AGA) young women. Metabolic evaluations included the composite-insulin sensitivity index (composite ISI). Serum RBP4 was measured with a competitive enzyme-linked immunosorbent assay (ELISA). RBP4 levels were similar in LBW and term AGA women, while composite ISI was significantly lower in the former group. With multivariate logistic regression analysis hormonal contraception (HC) use but not birth weight, diabetes in either parents and body mass index was significantly associated with higher RBP4 levels: odds ratio = 10.6; 95% confidence interval (CI) = 2.4-76.6. In spite of higher RBP4 levels in women under HC, composite ISI was similar in women with or without HC. Women under HC also exhibited significantly higher levels of sex hormone binding globulin (SHBG), triglycerides, cholesterol, and C-reactive protein (CRP), and all of them, but not composite ISI, were significantly correlated with RBP4 levels. In conclusion, RBP4 serum level was not a marker of IR but, for the first time, it is documented a sustained increase of serum RBP4 under HC. Pathophysiological and clinical significance of this novel finding requires further investigations.