What do systematic reviews say?

Higher paternal education vs Lower paternal education

Higher paternal education was associated with lower DMFT.

• Oral Health of Children and Adolescents in the United Arab Emirates: A Systematic Review of the Past Decade. 2021 All outcomes

  Overall
  Regression coefficient -0.35 [-0.53, -0.17]
  1 study · 803 participants
  GRADE not reported

Higher waist circumference vs Lower waist circumference

Waist circumference was not significantly associated with childhood dental caries (pooled OR 1.08, 95% CI 0.90 to 1.30; I2=47.7%); ungraded.

• Childhood obesity in relation to risk of dental caries: a cumulative and dose-response systematic review and… 2024 All outcomes

  Dental examinations of children; 15 countries across Europe, Asia, the Americas and Oceania
  OR 1.08 [0.90, 1.30]
  2 studies
  GRADE not reported

Higher parental education (tertiary) vs Lower parental education (reference)

Paternal tertiary education was associated with lower odds of ECC (OR 0.381).

• Prevalence and risk factors for early childhood caries in North Africa: a systematic review and meta-analysis. 2025 All outcomes

  Egypt (Kabil 2017) · Paternal tertiary education [Kabil]
  OR 0.381 [0.16, 0.91]
  1 study
  GRADE not reported
• Prevalence and risk factors for early childhood caries in North Africa: a systematic review and meta-analysis. 2025 All outcomes

  Egypt (Kabil 2017) · Maternal tertiary education [Kabil]
  OR 0.083 [0.03, 0.21]
  1 study
  GRADE not reported
• Prevalence and risk factors for early childhood caries in North Africa: a systematic review and meta-analysis. 2025 All outcomes

  Tunisia (Chouchene 2022) · Parents' education level [Chouchene]
  OR 0.797 [0.171, 0.650]
  1 study
  GRADE not reported

Higher mean patient age (per 1 year) vs Lower mean patient age (per 1-year decrement)

In the mandible, mean patient age was not significantly associated with space closure odds (OR 0.59 per year; not GRADE-rated).

• Spontaneous space closure after extraction of permanent first molars in children and adolescents: a systematic review… 2024 All outcomes

  Until eruption of the permanent second molar (median follow-up 4.0 years) · University clinics and hospitals in 8 countries (children/adolescents <18 years) · Mandible
  OR 0.59 [0.20, >100.00]
  3 studies
  GRADE not reported

Higher parental / maternal education vs Lower parental education (reference)

Higher parental education is associated with better OHRQoL in adolescents (narrative synthesis; no pooled estimate or GRADE rating).

• Oral-health-related quality of life in adolescents: umbrella review. 2023 All outcomes

  Community/school/clinic settings; adolescents 10-19 years; included reviews conducted in multiple countries
  Adolescents from families with higher incomes and higher levels of maternal education have better OHRQoL scores [34]. Children from families with high income, parental education and family economy had better OHRQoL [42].
  Studies not reported
  GRADE not reported

Higher circulating 25-hydroxyvitamin D (25(OH)D) concentration vs Lower circulating 25-hydroxyvitamin D (25(OH)D) concentration

The meta-analysis of observational studies reported a SMD (to OR) of 0.08 (95% CI 0.01 to 0.63) for higher versus lower circulating vitamin D concentration.

• Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational… 2014 All outcomes
  SMD (to OR) 0.08 [0.01, 0.63]
  7 studies · 1005 participants
  GRADE not reported

Higher circulating 25-hydroxyvitamin D (25(OH)D) concentration vs Lower circulating 25-hydroxyvitamin D (25(OH)D) concentration

The meta-analysis of observational studies reported a OR of 0.88 (95% CI 0.68 to 1.15) for higher versus lower circulating vitamin D concentration.

• Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational… 2014 All outcomes
  OR 0.98 [0.84, 1.15]
  6 studies · 4524 participants
  GRADE not reported

Higher circulating 25-hydroxyvitamin D (25(OH)D) concentration vs Lower circulating 25-hydroxyvitamin D (25(OH)D) concentration

The meta-analysis of observational studies reported a SMD (to OR) of 0.29 (95% CI 0.19 to 0.46) for higher versus lower circulating vitamin D concentration.

• Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational… 2014 All outcomes
  SMD (to OR) 0.29 [0.19, 0.46]
  7 studies · 534 participants
  GRADE not reported

Higher circulating 25-hydroxyvitamin D (25(OH)D) concentration vs Lower circulating 25-hydroxyvitamin D (25(OH)D) concentration

The meta-analysis of observational studies reported a SMD (to OR) of 0.31 (95% CI 0.23 to 0.42) for higher versus lower circulating vitamin D concentration.

• Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational… 2014 All outcomes
  SMD (to OR) 0.31 [0.23, 0.42]
  28 studies · 2956 participants
  GRADE not reported

Higher circulating 25-hydroxyvitamin D (25(OH)D) concentration vs Lower circulating 25-hydroxyvitamin D (25(OH)D) concentration

The meta-analysis of observational studies reported a RR of 0.88 (95% CI 0.81 to 0.93) for higher versus lower circulating vitamin D concentration.

• Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational… 2014 All outcomes
  RR 0.86 [0.81, 0.92]
  10 studies · 6853 participants
  GRADE not reported

Higher national income (GNI per capita) vs Lower national income (GNI categories: middle <=$15,000 / high $15,001-25,000 / very high >$25,000)

Higher national income was strongly associated with lower odds of poor oral health (OR 0.10, 95% CI 0.03 to 0.37; about 90% lower odds); not GRADE-rated.

• Caries status in 12-year-old children, geographical location and socioeconomic conditions across European countries: A… 2025 All outcomes

  Cross-sectional (survey data 2011-2022) · European countries; ordinal logistic regression of DMFT category on socioeconomic indicators (adjusted) · Higher vs lower income (ordinal logistic regression, adjusted)
  OR 0.10 [0.03, 0.37]
  Studies not reported
  GRADE not reported

Sugar consumption (higher sugar intake) vs No sugar consumption (lower/no intake)

Higher sugar consumption is associated with early childhood caries in children under 6 years: pooled OR 1.59 (95% CI 1.50 to 1.68) from 9 cohort studies with no heterogeneity (I2=0%); the body of evidence was not GRADE-rated (ungraded).

• Sugar consumption and early childhood caries: a systematic review and meta-analysis of cohort studies. 2025 All outcomes

  Outcome (ECC) assessed from 9 months to 5 years of age · Population-based birth and childhood cohort studies; multiple countries (Europe, Brazil, Asia, Australia, USA); mostly high-income, six in developing countries (Brazil, Thailand), none in low-income countries · Overall (all 9 meta-analyzed studies pooled)
  OR 1.59 [1.50, 1.68]
  9 studies
  GRADE not reported

Higher national income (GNI per capita) vs Lower national income (GNI categories: middle <=$15,000 / high $15,001-25,000 / very high >$25,000)

Mean DMFT in 12-year-olds rises as national income falls: 0.90 (very high income), 2.38 (high income), 3.30 (middle income) (Figure 2); not GRADE-rated.

• Caries status in 12-year-old children, geographical location and socioeconomic conditions across European countries: A… 2025 All outcomes

  Cross-sectional (survey data 2011-2022) · European countries stratified by World Bank GNI per capita (modified 3-category); test of group differences Q_b(2)=51.35, p<0.01 · Very high income (GNI >$25,000)
  MEAN 0.90 [0.66, 1.15]
  14 studies
  GRADE not reported
• Caries status in 12-year-old children, geographical location and socioeconomic conditions across European countries: A… 2025 All outcomes

  Cross-sectional (survey data 2011-2022) · European countries stratified by World Bank GNI per capita (modified 3-category); test of group differences Q_b(2)=51.35, p<0.01 · High income (GNI $15,001-25,000)
  MEAN 2.38 [1.78, 2.97]
  8 studies
  GRADE not reported
• Caries status in 12-year-old children, geographical location and socioeconomic conditions across European countries: A… 2025 All outcomes

  Cross-sectional (survey data 2011-2022) · European countries stratified by World Bank GNI per capita (modified 3-category); test of group differences Q_b(2)=51.35, p<0.01 · Middle income (GNI <=$15,000)
  MEAN 3.30 [2.57, 4.03]
  12 studies
  GRADE not reported

Higher family income / socioeconomic status vs Lower income / worse socioeconomic status

Higher family income / better socioeconomic status is associated with better OHRQoL in adolescents (narrative synthesis; no pooled estimate or GRADE rating).

• Oral-health-related quality of life in adolescents: umbrella review. 2023 All outcomes

  Community/school/clinic settings; adolescents 10-19 years; included reviews conducted in multiple countries
  Adolescents from families with higher incomes and higher levels of maternal education have better OHRQoL scores [34]. Worse oral health status, older age, female sex and worse socioeconomic status were significantly…
  Studies not reported
  GRADE not reported

Higher circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) concentration vs Lower circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) concentration

The meta-analysis of observational studies reported a OR of 0.99 (95% CI 0.87 to 1.12) for higher versus lower circulating vitamin D concentration.

• Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational… 2014 All outcomes
  OR 0.99 [0.87, 1.14]
  7 studies · 3640 participants
  GRADE not reported

Higher circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) concentration vs Lower circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) concentration

The meta-analysis of observational studies reported a OR of 0.99 (95% CI 0.68 to 1.47) for higher versus lower circulating vitamin D concentration.

• Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational… 2014 All outcomes
  OR 0.99 [0.68, 1.44]
  3 studies · 3627 participants
  GRADE not reported

Higher BMI (continuous / per-unit increment) vs Lower BMI (continuous reference / per 1 kg/m2 decrement)

Pooling studies that used BMI as a continuous variable showed no significant association between per-unit BMI and childhood dental caries (OR 1.01, 95% CI 0.99 to 1.03; I2=3.5%); ungraded.

• Childhood obesity in relation to risk of dental caries: a cumulative and dose-response systematic review and… 2024 All outcomes

  Dental examinations of children; 15 countries across Europe, Asia, the Americas and Oceania · Continuous BMI, direct pooling (studies reporting BMI as a continuous variable)
  OR 1.01 [0.99, 1.03]
  4 studies
  GRADE not reported
• Childhood obesity in relation to risk of dental caries: a cumulative and dose-response systematic review and… 2024 All outcomes

  Dental examinations of children; 15 countries across Europe, Asia, the Americas and Oceania · Non-linear dose-response (restricted cubic splines)
  Fig. 5: significant non-linear (restricted cubic spline) dose-response between BMI and childhood dental caries; relative risk rises at higher BMI (curve reaches ~2.4-2.9 at BMI 30-35) and is also elevated among…
  Studies not reported
  GRADE not reported
• Childhood obesity in relation to risk of dental caries: a cumulative and dose-response systematic review and… 2024 All outcomes

  Dental examinations of children; 15 countries across Europe, Asia, the Americas and Oceania · Linear dose-response (GLST, per 1 kg/m2 BMI increment)
  OR 1.01 [1.00, 1.03]
  16 studies
  GRADE not reported

Higher consumption of snacks / sugar / soft drinks vs Lower consumption

Higher snacking and soft-drink/sugar consumption were associated with more caries in most studies, though one study found no association with sweet-consumption frequency (narrative synthesis; not GRADE-rated).

• Oral Health of Children and Adolescents in the United Arab Emirates: A Systematic Review of the Past Decade. 2021 All outcomes

  UAE; schools (Ajman, Sharjah), nurseries (Ras Al Khaimah)
  Soft drink consumption (Khadri et al.: 0.31, 95% CI 0.14-0.47) and a high extent of snacking (Hashim et al.: high vs low snack level aRR 1.46, 95% CI 1.26-1.70; snacking >=3x vs once daily aRR 1.25, 1.00-1.57) were…
  Studies not reported
  GRADE not reported

Higher per-capita expenditure on dental health care vs Lower per-capita expenditure on dental health care (USD bands: $0-50 / $51-100 / >$100)

Countries with higher per-capita dental expenditure had lower mean DMFT (>$100: 0.96; $51-100: 2.14; $0-50: 3.06) (Figure 4); not GRADE-rated.

• Caries status in 12-year-old children, geographical location and socioeconomic conditions across European countries: A… 2025 All outcomes

  Cross-sectional (survey data 2011-2022) · European countries stratified by OECD per-capita dental health-care expenditure (USD); test of group differences Q_b(2)=30.51, p<0.01; expenditure-stratified overall pooled DMFT 2.10 (95% CI 1.61-2.59), 32 countries · $0-50 per capita
  MEAN 3.06 [2.32, 3.79]
  14 studies
  GRADE not reported
• Caries status in 12-year-old children, geographical location and socioeconomic conditions across European countries: A… 2025 All outcomes

  Cross-sectional (survey data 2011-2022) · European countries stratified by OECD per-capita dental health-care expenditure (USD); test of group differences Q_b(2)=30.51, p<0.01; expenditure-stratified overall pooled DMFT 2.10 (95% CI 1.61-2.59), 32 countries · >$100 per capita
  MEAN 0.96 [0.64, 1.28]
  12 studies
  GRADE not reported
• Caries status in 12-year-old children, geographical location and socioeconomic conditions across European countries: A… 2025 All outcomes

  Cross-sectional (survey data 2011-2022) · European countries stratified by OECD per-capita dental health-care expenditure (USD); test of group differences Q_b(2)=30.51, p<0.01; expenditure-stratified overall pooled DMFT 2.10 (95% CI 1.61-2.59), 32 countries · $51-100 per capita
  MEAN 2.14 [1.40, 2.89]
  6 studies
  GRADE not reported

Keratinocyte growth factor (KGF), higher dose/regimen vs Keratinocyte growth factor (KGF), different (lower) dose/regimen

• Interventions for preventing oral mucositis in patients with cancer receiving treatment: cytokines and growth factors 2017 · Cochrane All outcomes
  Some inconsistent evidence from which no conclusions can be drawn regarding different dosages of KGF (Analyses 2.1 to 2.8); no pooled estimate reported
  Studies not reported
  GRADE not reported