Hypertension and Happiness

Hypertension and Happiness across Nations

David G. Blanchflower and Andrew J. Oswald

Journal of Health Economics 27(2): 218-233.

Abstract
In surveys of well-being, countries such as Denmark and the Netherlands emerge as particularly happy while nations like Germany and Italy report lower levels of happiness. But are these kinds of findings credible? This paper provides some evidence that the answer is yes. Using data on 16 countries, it shows that happier nations report systematically lower levels of hypertension. As well as potentially validating the differences in measured happiness across nations, this suggests that blood-pressure readings might be valuable as part of a national well-being index. A new ranking of European nations’ GHQ N6 mental-health scores is also given.

Ungated version:

http://www2.warwick.ac.uk/fac/soc/economics/research/workingpapers/publications/twerp_828.pdf

How not to do Instrumental variables

Instrumental Variable estimation, Generalized Method of Moments and related techniques are part of the standard toolkit for applied economists. They are also increasingly used in other fields such as health.
What everyone knows, or should know, is that while one can think of these models as a two stage process this is not actually how you do it. But this paper which looks at how systolic blood pressure depends on anti-hypertensive drugs in Japan, published in the Bulletin of the World Health Organization 2008, gets it badly wrong. As they note, a simple regression of blood pressure on medication is likely to get a positive slope so you need to instrument or do something.
They estimate a logit and then stick the predicted values into an OLS model. Aside from the identifying assumption (which isn't discussed & looks pretty dodgy to me), this is not IV as usually defined and it is not clear that the estimate is consistent or that the standard errors are correct. The model also includes controls for exercise but these are also likely to be endogenous but this is ignored.

Boys Live Dangerously in the Womb

American Journal of Human Biology, 2010 May-Jun;22(3):330-5.

Eriksson JG, Kajantie E, Osmond C, Thornburg K, Barker DJ.

Abstract

The growth of every human fetus is constrained by the limited capacity of the mother and placenta to deliver nutrients to it. At birth, boys tend to be longer than girls at any placental weight. Boy's placentas may therefore be more efficient than girls, but may have less reserve capacity. In the womb boys grow faster than girls and are therefore at greater risk of becoming undernourished. Fetal undernutrition leads to small size at birth and cardiovascular disorders, including hypertension, in later life. We studied 2003 men and women aged around 62 years who were born in Helsinki, Finland, of whom 644 had hypertension: we examined their body and placental size at birth. In both sexes, hypertension was associated with low birth weight. In men, hypertension was also associated with a long minor diameter of the placental surface. The dangerous growth strategy of boys may be compounded by the costs of compensatory placental enlargement in late gestation. In women, hypertension was associated with a small placental area, which may reduce nutrient delivery to the fetus. In men, hypertension was linked to the mothers' socioeconomic status, an indicator of their diets: in women it was linked to the mothers' heights, an indicator of their protein metabolism. Boys' greater dependence on their mothers' diets may enable them to capitalize on an improving food supply, but it makes them vulnerable to food shortages. The ultimate manifestation of their dangerous strategies may be that men have higher blood pressures and shorter lives than women.