John R. Lukacs, professor of anthropology at the University of Oregon, who specializes in dental, skeletal, and nutritional issues, reproductive pressures, and rising fertility, explains why women have a more rapid decline in dental health than men.
The conclusion follows a comprehensive review of records of the frequencies of dental cavities in prehistoric and living human populations from research done around the world. A driving factor was dramatic changes in female-specific hormones, Lukacs reported.
The study examined the frequency of dental caries by sex to show that women typically experience poorer dental health than men. Among the research reviewed were studies previously done by Lukacs. Two clinical dental studies published this year (one done in the Philippines, the other in Guatemala) point to the same conclusions and "may provide the mechanism through which the biological differences are mediated," Lukacs says.
A change in food production by agrarian societies has been associated with an increase in cavities. Anthropologists have attributed men-women differences to behavioral factors, including a sexual division of labor and dietary preferences. However, Lukacs said, clinical and epidemiological literature from varied ecological and cultural settings reveals a clear picture of the impacts on women’s oral health.
"The role of female-specific factors has been denied by anthropologists, yet they attain considerable importance in the model proposed here, because the adoption of agriculture is associated with increased sedentism and fertility," Lukacs said. "I argue that the rise of agriculture increased demands on women’s reproductive systems, contributing to an increase in fertility that intensified the negative impact of dietary change on women’s oral health. The combined impacts of increased fertility, dietary changes, and division of labor during the move into agricultural societies contributed to the widespread gender differential observed in dental caries rates today."
Lukacs’ meta-analysis repeatedly found that increases in cavities go in favor of women in adulthood. Lukacs’ review found that women’s higher rates of cavities are influenced by three main changes:
• Female sex hormones. He notes that hormones and associated physiological factors can significantly impact cavity formation. A study on animals published in 1954 found that female estrogens, but not male androgens, were correlated to cavity rates. He argues for a cumulative effect of estrogens, including fluctuations at puberty and high levels during pregnancy that promote cavities and dietary changes.
• The biochemical composition and flow rate of saliva. Women produce less saliva than do men, reducing the removal of food residue from the teeth, and that during pregnancies the chemical composition changes, reducing saliva’s antimicrobial capacity.
• Food cravings, immune response, and aversions during pregnancy. Lukacs points to findings that women crave high-energy, sweet foods during the third trimester, and have an aversion to meat in first trimester.
How the factors contribute to higher risk of cavities in women as they age is not fully documented or understood, he wrote.
"However, if hormonal and physiological factors work in an independent or additive manner, their impact on women’s oral health could be significant. The fact that women’s caries experience increases with age at a greater rate than men’s in diverse ethnic groups from different ecological and cultural settings supports this interpretation," Lukacs said.
