Dental caries is the world’s most prevalent disease and remains a significant worldwide public health problem. While disease levels are falling in many countries it disproportionately affects those from more disadvantages backgrounds.

The aim of this review was to assess current evidence for the association between socioeconomic position (SEP) and caries.

Methods

Searches were conducted in the Medline, Embase, CINAHL, Web of Science, Cochrane Central Database, and Campbell Library databases. Pro-and retrospective cohort, case-control, and cross-sectional studies investigating the association between own or parental educational or occupational background or income and dental caries prevalence, experience, or incidence published in English were considered.

Two reviewers carried out study selection and data abstraction independently. Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) Only studies reporting or allowing the calculation of odds ratios (OR) and error estimates (confidence intervals [CIs], standard error [SE], P values) were used for quantitative data synthesis.

Results

• 155 studies (reported in 170 articles) involving a total of 329,798 participants were included.
• 24 were cohort studies, 9 case-control studies and 122 cross-sectional.
• The majority (88) were in highly developed countries, 44 in developing countries, 22 in underdeveloped counties and 1 in several countries.
• 11 studies were considered to be of high quality, 100 of moderate quality and 44 of low quality.
• From all studies, 83 found 1 or more caries parameter to be significantly higher in low-SEP compared with high-SEP individuals, while only 3 studies found the opposite.
• 92 studies contributed to the meta-analysis, which is summarised in the table below.

	Association between SEP and caries prevalenceOdds ratio (95% CI)	Association between SEP and having any caries experience [DMFT/dmft >0]Odds ratio (95% CI)
Low compared with high educational background	1.48 (1.34-1.63)	1.29 (1.14-1.45)
Low compared with high income	1.29 (1.13-1.41)	1.40 (1.19 –1.65)
Low compared with high occupational background	1.30 (1.13-1.49)	1.21 (1.03-1.41)

• The association between low educational background and having DMFT/dmft > 0 was significantly increased in highly developed countries (R² = 1.32 [0.53-2.13].
• Publication bias was present but did not significantly affect the estimates

Conclusions

The authors concluded

Studies included within this review used a variety of SEP or caries measures and reported outcomes, which is problematic for quantitative synthesis, and evidence stemming from these studies is of limited quality. Nevertheless, a vast number of studies indicate an association between SEP and caries. Low SEP is associated with a higher risk of having caries lesions or caries experience. This association might be stronger in developed countries. Established diagnostic and treatment concepts might not account for the unequal distribution of caries.

Commentary

The authors highlight the limitations of the evidence supporting their findings, which in part stems from, the variety of study designs caries measures, detection cutoffs and statistical models and scales. They have chosen to included all the study designs in the meta-analysis and it would have been interesting to see this results obtained from just the 11 high quality studies.

Links

Original Review Protocol

Schwendicke F, Dörfer CE, Schlattmann P, Page LF, Thomson WM, Paris S. Socioeconomic Inequality and Caries: A Systematic Review and Meta-Analysis. J Dent Res. 2014 Nov 13. pii: 0022034514557546. [Epub ahead of print] Review. PubMed PMID: 25394849.