Abstract and Introduction
While the geographic and demographic disparities in the prevalence of hypertension have been recognized for decades, the reasons for these differences in disease risks remain unknown. The demographic and geographic patterns of hypertension are similar to those of low birth weight, giving support to the "Barker Hypothesis" which proposes a fetal origin of adult-onset disease. In fact, ecologic and observational studies throughout the world have detected significant associations of low birth weight and increased risks of hypertension. Nonetheless, the mechanisms for the association have not been fully described and documented. With some supportive evidence, proposed mechanisms include reduced nephrogenesis with a higher threshold for pressure natriuresis and greater susceptibility to progressive renal disease, impaired development of the endothelium, and increased sensitivity to glucocorticoids. Still, considerable work needs to be done to explain the birth weight/blood pressure relationship. The findings to date and the clinical significance warrant continued research in this intriguing area of study.
The risks and adverse health outcomes associated with elevated blood pressures have been well documented and recognized. Cardiovascular disease, cerebrovascular disease, and end-stage renal disease account for a major health burden in populations worldwide. While hypertension has been identified as a common factor for a significant proportion of these conditions, the pathogenic mechanisms by which low birth weight contributes to a greater risk for hypertension and cardiovascular diseases have not been fully elucidated. The burden of hypertension is substantial, with approximately one fourth of the adult population in the United States affected. Further complicating the risk estimates are the significant demographic and geographic differences in the prevalence of hypertension (Figure 1). For example, African American men have the highest prevalence of hypertension compared to the other race-sex groups, with African American men in the South having an even greater risk for high blood pressure than residents from other parts of the country. The factors associated with these differences and disparities remain unclear. However, these demographic and geographic patterns are evident in other conditions such as low birth weight (Figure 2). Such ecologic associations form the basis for the "Barker Hypothesis" that proposes that adult-onset disease has a fetal and early life origin.[3,4,5] The association of fetal and early-life indicators and adult-onset disease has been well documented in many populations worldwide.[3,4,5,6] Ecologic and descriptive studies identified significant associations of population disease rates from cardiovascular disease and infant mortality. More recent analyses[5,6] have been refined with cohort-based studies finding low birth weights associated with higher blood pressures and altered glucose and insulin metabolism in children and adults. Again, the mechanisms for these relationships between birth weight and health outcomes for hypertension and related complications remain to be determined. This paper summarizes several of the proposed mechanisms for the relationship of birth weight to cardiovascular and renal risk factors and disease.
Prevalence of hypertension in the Southern United States according to the Third National Health and Nutrition Examination Survey (NHANES III) Age-adjusted percent of adult population with hypertension defined as a blood pressure of 140/90 mm Hg and/or being medically treated for high blood pressure; *Northeast, Central, and West. Summarized from Hall et al.
Low birth weight* in the Southern United States, 2000. *Percent of births with low birth weight (less than 2500 g, or 5 lb 8 oz). Rates were calculated from data provided in Marten JA et al.
© 2003 Le Jacq Communications, Inc.
Cite this: Low Birth Weight as a Risk Factor for Hypertension - Medscape - Mar 01, 2003.