Social Factors Associated with Readiness for Sexual Activity in Adolescents: A Population-Based Cohort Study

Archives of Sexual Behavior - Various factors are associated with sexual activity in adolescence and it is important to identify those that promote healthy and adaptive romantic and sexual...     

Could associations between breastfeeding and insulin‐like growth factors underlie associations of breastfeeding with adult chronic disease? The Avon Longitudinal Study of Parents and Children

Objective The influence of infant feeding method (breast/formula) on growth factor levels could underlie associations of breastfeeding with childhood growth and risk factors for cardiovascular disease. We investigated associations of having been breastfed with serum IGF‐I and IGFBP‐3 in childhood. Methods Prospective birth cohort study (subsample of the Avon Longitudinal Study of Parents and Children, UK) based on 871 children born in 1991/1992 who underwent clinical follow‐up and blood tests at age 7–8 years. A total of 488 (56%) children had complete data. Results In children with complete data, the age‐ and sex‐standardized IGF‐I levels of those who were partially or exclusively breastfed were 6·1 and 13·8 ng/ml higher, respectively, than those who were never breastfed (increase in IGF‐I levels per category of breastfeeding exclusivity: 7·1 ng/ml; 95% CI: 0·3–13·9; P = 0·04). In models also controlling for birthweight, gestational age, mother's age, and socioeconomic and dietary factors, the breastfeeding–IGF‐I association was attenuated (regression coefficient: 3·3 ng/ml; ?4·2–10·7; P = 0·4); further adjustment for IGFBP‐3 made little difference (regression coefficient: 4·1 ng/ml; ?2·8–10·9; P = 0·2). There was little evidence for an association between breastfeeding and IGFBP‐3 or the molar ratio IGF‐I/IGFBP‐3. Conclusions The positive association between breastfeeding and IGF‐I could be due to residual confounding or to chance. Nevertheless, the magnitude of the fully adjusted effect estimate and the novelty of the association suggest that larger studies should now be conducted to confirm or refute the hypothesis that variations in IGF‐I by infant feeding mode explain associations of breastfeeding with health in later life.     

Immunologic status of hemophilia patients treated with cryoprecipitate or lyophilized concentrate

We evaluated 37 patients with moderate or severe hemophilia A and six patients with severe factor IX deficiency for clinical or laboratory evidence of immune abnormalities. Patients were assigned to one of four groups according to the type of clotting factor replacement. Twenty patients had received only cryoprecipitate during the two years preceding the evaluation (group I); 11 additional patients were treated predominantly with cryoprecipitate but had also received up to nine bottles of factor VIII concentrate (group II); six patients received factor VIII concentrate (group III); six patients received factor IX concentrate (group IV). There was no clinical or laboratory evidence of immunodeficiency among the 43 patients. The mean absolute number of Th cells was normal in all patient groups, but the mean absolute number of Ts cells was increased compared with controls, both in patients treated with cryoprecipitate and in patients treated with factor VIII or factor IX concentrate. There was no correlation between the Th/Ts ratio and patient age, alanine aminotransferase level, hepatitis serology, in vitro lymphocyte function, or amount of clotting factor administered. Our observations demonstrate that the volunteer or commercial origin of clotting factor replacement cannot fully explain the alterations in lymphocyte subset distribution previously described in patients with hemophilia A.     

First-time donors responding to a national disaster may be an untapped resource for the blood centre

Background On 12 May 2008, a severe earthquake struck Sichuan in China. Many people donated blood for the first time, leading us to question whether these donors might become repeat donors in the future. The return pattern of post‐earthquake first‐time donors (PEFTD) was compared with that of first‐time donors (FTD) in a comparable period. Methods Demographic characteristics, transfusion‐transmissible infection rates and 1‐year return rates were compared between 5147 PEFTD (5/13‐5/19, 2008) and 3176 FTD (5/13‐5/19, 2009) from five Chinese blood centres using chi‐squared tests. Adjusted logistic regression was used to detect earthquake effect on donor return. Results Post‐earthquake first‐time donors were more frequently between 26 and 45 years, men, and better educated compared with the control group. Slightly higher but not statistically significant increased rates of hepatitis B virus surface antigen (HBsAg) (0·87% vs. 0·50%, P = 0·054), hepatitis C virus (HCV) (0·70% vs. 0·63%, P = 0·414), syphilis (0·9% vs. 0·7%, P = 0·489) and lower rates of human immunodeficiency virus (HIV) (0·31% vs. 0·60%, P = 0·078) reactivity were detected for PEFTD. The 1‐year return rate for PEFTD was significantly lower than that of the controls (8·0% vs. 13·0%, P < 0·001). After adjusting for demographic factors, donation volume and sites, the PEFTD were less likely to return in 1 year than the controls (OR: 0·520; 95% CI: 0·442, 0·611). Conclusion Post‐earthquake first‐time donors may be less likely to donate again without continuing motivation strategies. Further studies on PEFTD’s lack of motivation to return for donation are needed to design recruitment strategies to convert PEFTD to become repeat donors to continuously replenish the blood supply.