Disentangling associations between pubertal development, healthy activity behaviors, and sex in adolescent social networks.

With the onset of puberty, youth begin to choose their social environments and develop health-promoting habits, making it a vital period to study social and biological factors contextually. An important question is how pubertal development and behaviors such as physical activity and sleep may be differentially linked with youths' friendships. Cross-sectional statistical network models that account for interpersonal dependence were used to estimate associations between three measures of pubertal development and youth friendships at two large US schools drawn from the National Longitudinal Study of Adolescent to Adult Health.

Safety in stigmatizing? Instrumental stigma beliefs and protective sexual behavior in Sub-Saharan Africa.

How are people's expression of HIV stigma beliefs connected to their own personal decisions concerning safe sexual practices? Does this relationship vary across countries and by the national context in which people reside? To answer these questions, we develop and test individual, contextual, and cross-level interactional hypotheses of the impact of instrumental HIV stigma attitudes on several measures of protective sexual behavior. Using Demographic and Health Survey data from 467,656 unpartnered individuals across 34 sub-Saharan African countries, we first find that counterintuitively, conservative HIV stigma attitudes are associated with lower likelihoods of participating in all types of protective sexual behaviors. Second, this negative relationship is most pronounced in the Southern and Eastern regions of Africa, where HIV prevalence is highest.