Tuesday, September 23, 2008

Sexually active girls get depressed?

The journal abstract is here. Prepublication version here. The authors have made some attempts at control but I cannot see that they have ruled out the possibility that girls who have low self-esteem to start with might consent to sex at a younger age. We could have the cart before the horse here

YOUNG girls who are sexually active are far more likely to suffer from depression than those who remain virgins, according to a controversial study. Academics found that teenage sex leaves many girls with feelings of guilt and low self-esteem.

Following a study of more than 14,000 US teens aged between 14 and 17, researchers said the feelings could be directly ascribed to sexual activity, rather than outside influences. The study, published in the Journal of Health Economics, found that having sex doubled the chances of girls becoming depressed, with 19 per cent of those who had sex exhibiting symptoms of depression, compared with 9.2 per cent who had abstained. The study also found that the mental health of boys in the same age group did not correlate with sexually active.



This is an amusing one. Some more cart before the horse logic. The authors find that people are slimmer where there are more doctors. But, despite hailing from good old class-conscious England, they have missed the obvious. Middle class people are slimmer and live in nicer areas. And doctors like living in nicer areas and seeing middle class people. So it is nicer areas that cause both the slimness and the increased presence of doctors. The presence of more doctors is not causal. Abstract follows:

GP supply and obesity

By Stephen Morris and Hugh Gravelle


We investigate the relationship between area general practitioner (GP) supply and individual body mass index (BMI) in England. Individual level BMI is regressed against area whole time equivalent GPs per 1000 population plus a large number of individual and area level covariates. We use instrumental variables (area house prices and age weighted capitation) to allow for the endogeneity of GP supply. We find that that a 10% increase in GP supply is associated with a mean reduction in BMI of around 1 kg/m2 (around 4% of mean BMI). The results suggest that reduced list sizes per GP can improve the management of obesity.


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