The study found that the Stout and Paine rib equation underestimated the age of all individuals in the sample by an average of 29.2 years. There are several potential explanations for these results. Metabolic disorders and dietary deficiencies have been suggested as causing either increased bone turnover rates that produce more secondary osteons (a long narrow cylinder) per area of bone than is considered normal, or can lead to lower bone turnover rates, resulting in fewer secondary osteons per bone volume than is expected for a given age. Many of the skeletal cases examined by forensic anthropologists are of individuals who had lifestyles that compromised their diet and health status; for example, forensic anthropologists who work with mass burials in international human rights cases often encounter undernourished populations. The original rib equation for age estimation developed by Stout and Paine used rib samples of individuals who had a better diet potential than the South-African Blacks from the Raymond Dart collection used in the current study. It is clear from this study that future histological age-estimating formulas must consider dietary and health-related effects on bones. The 26 individuals examined in this study had died from either general malnutrition or pellagra, a chronic disease caused by a deficiency of nicotinic acid in the diet. The methods used in following the Stout and Paine equation for determining skeletal age at death are described in detail. 2 figures, 2 tables, and 16 references