“…Confounding factors can mask an association or even falsely indicate a causal relationship between a risk factor and outcome , which justifies the adjustment for confounders of the outcome by means of multivariate statistics. Several studies included in the present review included confounding factors in the multivariate analyses, such as demographic and socio‐economic characteristics, clinical conditions (teeth with caries, missing teeth, maximum vertical mandibular movement, treatment needs, tooth sensitivity, dry mouth, toothache, orofacial pain and functional dentition), the use of services, oral hygiene habits, smoking, dietary habits, self‐rated oral health, difficulty speaking, systemic diseases and work‐related stress .…”