Question

The table below shows data from Rich-Edwards et al. (2005) on the prevalence of various afflictions among female nurses who were born at different weights. Use the table to answer the following questions: a. Summarize the data in the figure in one or two concise sentences. b. Discuss the data in light of what you know about the thrifty phenotype hypothesis. C. How would you use the Grossman model to formalize the thrifty phenotype hypothesis? Cohort Average birth weight 3.2-3.9 100% 100% Low birth weight 2.5-3.2 130% 116% Extremely low birth weight < 2.3 Birth weight (kg) Coronary heart disease Stroke All cardiovascular disease Very low birth weight 2.3-2.5 148% 105% 129% 131% 123% 100% 123% 127% Indicates statistically significant difference from the average birth weight cohort. Hazard ratios are adjusted for age and body mass index (BMI). Source: Data from Table 1 in Rich-Edwards et al. (2005).

Answer 1

a) The given data shows the risk of coronary heart disease, stroke and all cardiovascular disease increases as there is more decrease in birth weight. These data provide strong evidence of an association between birth weight and adult coronary heart disease and stroke.

b) The thrifty phenotype hypothesis says that reduced fetal growth is strongly associated with a number of chronic conditions later in life. This increased susceptibility results from adaptations made by the fetus in an environment limited in its supply of nutrients.The thrifty phenotype is a component of the fetal origins hypothesis. These chronic conditions include coronary heart disease, stroke, diabetes, and hypertension. Now here the reduced fetal growth is the decreasing birth weight. This reducing birth weight due to nutrition issues increases the risk of coronary heart disease , stroke and all cardiovascular disease in adult women. It is evident from the data that women with average birth weight that is 3.2 -3.9 has less chances of developing cornory disesase than women in other category.

c) Grossman derives the demand for health from an optimal control model in which health capital is both a consumption and an investment good. In his approach, the individual chooses his level of health and therefore his life span. Initially an individual is endowed with a certain amount of health capital, which depreciates over time but can be replenished by investments like medical care, diet, exercise, etc. Therefore, the level of health is not treated as exogenous but depends on the amount of resources the individual allocates to the production of health. The production of health capital also depends on variables which modify the efficiency of the production process, therefore changing the shadow price of health capital. For example, more highly educated people are expected to be more efficient producers of health who thus face a lower price of health capital, an effect that should increase their quantity of health demanded. While the Grossman model provides a suitable theoretical framework for explaining the demand for health and the demand for medical services, it has not been too successful empirically. However, empirical tests up to this date have been exclusively based on cross section data, thus failing to take the dynamic nature of the Grossman model into account.