Causal Effect of Tooth Loss on Cardiovascular Diseases.

Many studies suggest associations between oral health and cardiovascular diseases, but there is a lack of causal evidence. Exploiting exogenous variation in tooth loss in US adults due to differential childhood exposure to fluoridated water, this study investigated the causal effect of tooth loss on cardiovascular diseases. A total of 722,519 participants in the Behavioral Risk Factor Surveillance System (BRFSS) waves 2006, 2008, or 2010 (birth years 1940-1978) were included in the analytical sample. To identify the effect of tooth loss on having a history of coronary heart disease (CHD) or stroke, instrumental variable analysis exploited childhood exposure to drinking water fluoride as an instrument. The weighted prevalence of CHD and stroke histories was 5.1% and 2.1%, respectively. First-stage regression indicated that childhood exposure to drinking water fluoride was a strong instrument for the number of lost teeth in adulthood (coefficient -0.61; 95% confidence interval [CI] -0.80, -0.41; F = 37.47). The probability of CHD was significantly higher by 1.04 percentage points (95% CI 0.57, 1.50) per lost tooth. The effect of tooth loss on stroke was significant only for people aged >/=60 y (coefficient 0.93 percentage points; 95% CI 0.14, 1.71). These findings are supportive of a causal effect of tooth loss on cardiovascular diseases among US adults, particularly in older age.