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.

Causal Inference: Onward and Upward!

When announcing the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2021, the Royal Swedish Academy emphasized how conclusions about cause and effect can be drawn from natural experiments. But what can dental research learn from this? The economist's toolbox provides a number of methods for causal inference from observational data such as instrumental variables, regression discontinuity designs, or difference-in-differences analyses. Although the relevance of improving causal inference in dental research has repeatedly been highlighted in recent years, dental research still seems to reveal major room for improvement in the application of such methods. First, there seems to be an absence of causal literature on key essential research questions for oral health. Second, the diversity and diffusion of causal inferential methods in the dental literature seem very limited so far. Third, while dental research has widely been promoting the use of directed acyclic graphs (DAGs) to help conceptualize causal thinking, comparably little attention seems to have been paid to choosing and applying appropriate data-analytic approaches for causal inference. Fourth, similar to other fields of medicine, confusion seems to persist within the dental research community as to the use of causal language. If dental research is to secure a robust evidence base for promoting effective oral health interventions, we argue that dental research needs to move beyond its current methodological echo chamber and embrace a radically different approach to causal inference. We call for editors, reviewers, and authors to embrace a much more critically reflective approach to causal inference.

Causal effect of tooth loss on depression: evidence from a population-wide natural experiment in the USA.

AIMS: Depression severely affects people's health and well-being. Oral diseases have been suggested to be associated with depression, but so far, there is no causal evidence. This study aimed to identify the causal effect of tooth loss on depression among US adults in a natural experiment study. METHODS: Instrumental variable analysis was conducted using data from 169 061 respondents born in 1940-1978 who participated in the 2006, 2008 or 2010 waves of the Behavioral Risk Factor Surveillance System (BRFSS). Random variation in tooth loss due to differential childhood exposure to drinking water fluoride was exploited as an instrument. RESULTS: US adults who were exposed to drinking water fluoride in childhood had more remaining teeth, therefore providing a robust instrument (F = 73.4). For each additional tooth loss, depressive symptoms according to the eight-item Patient Health Questionnaire depression (PHQ-8) score increased by 0.146 (95% CI 0.008-0.284), and the probability of having clinical depression (PHQ ⩾10) increased by 0.81 percentage points (95% CI -0.12 to 1.73). CONCLUSIONS: Tooth loss causally increased depression among US adults. Losing ten or more teeth had an impact comparable to adults with major depressive disorder not receiving antidepressant drugs.

[Isometric grip strength and social gerontological research: results and analytic potentials of SHARE and SOEP]. / Isometrische Greifkraft und sozialgerontologische Forschung: Ergebnisse und Analysepotentiale des SHARE und SOEP.

This paper shows that the measurement of hand grip strength provides a non-invasive and reliable objective health indicator for social science research and is easy to collect in general population surveys. Grip strength is not only a useful complement of self-reported indicators of health, but it also exhibits a considerable predictive power with regard to a number of further relevant variables for social gerontological research, such as mortality risks. New data from the 2004 Survey of Health, Ageing and Retirement in Europe (SHARE) and the 2006 wave of the German Socio-Economic Panel Study (SOEP) allow insightful methodological and very first substantive cross-sectional analyses of grip strength in Germany. The focus of the present study is on the analysis of individuals aged 50 or older. The experience of both surveys when measuring grip strength is consistently positive, particularly with regard to the respondents' feedback. Major determinants of isometric grip strength are - beyond the individual's gender - age, body size and weight. A multivariate analysis also provides evidence for a clear positive association between various health indicators and grip strength.

[Vocationally motivated migration behavior in double-income households. An empirical analysis using GSOEP data]. / Beruflich bedingte Umzuge von Doppelverdienern. Eine empirische Analyse mit Daten des SOEP.

PIP: "Rational-choice or microeconomic approaches to migration behavior are often restricted to analysing the rational action of the (often male) head of household. These explanations do not allow for the fact that migration decisions are frequently made by whole families. In this context, the increasing labor force participation of married women is assumed to be one important reason for declining migration rates in Germany. In this paper, the relative effect of different job characteristics of men and women on the labor migration of double income households is examined using German household panel data (GSOEP). We find a sex related bias in family decision-making, which cannot be accounted for by classical microeconomic models of family migration. Sociological approaches to household decision-making emphasizing the importance of sex role ideologies held by family members can therefore be considered useful complements to purely economic models." (EXCERPT)^ieng