Table 3.

Summary of systematic reviews with data pertaining to Question 3^a

Review objectives	Review study inclusion criteria	Countries (WHO regions) of included relevant studies	Method of evidence synthesis and dental caries related outcomes	Included references data on dose responseb
Moynihan and Kelly [3]. AMSTAR Rating: High
To systematically review all available published data on amount of sugars consumption and levels of dental caries and to report the findings for both adults and children	Studies published 1950- 2011 RCTs, non-randomised trials, cohort, case controlled, cross sectional, ecological, reviews with new data. Studies reporting both amount of sugars and data on dental caries incidence, prevalence, count (DMFT/dmft, DMFS/dmfs, RCI,) Excluded theses, abstracts, and preprints All countries All languages	Argentina, Brazil, Denmark, Finland, Germany, Iceland, Iraq, Japan, Norway, Philippines, South Africa, Sweden, Switzerland, Turkey, UK, USA (African, Eastern Mediterranean, European, Southeast Asia, The Americas)	Meta-analysis and Vote Counting: 42/50 and 5/5 studies in children and adults respectively showed at least one positive sugars-caries association GRADE profile analysis classified evidence as moderate quality to support free sugars intake < 10% EI. Very low quality evidence to support free sugars < 5% EI. Log-linear relationship between sugars and caries increment between 0.2 kg and 5.0 to 7.5 kg/ person/year in teeth erupted for 7–8 yrs., r = 0.8 Meta-analysis indicated large effect size [SMD for DMFT 0.82 (95% CI: 0.67, 0.97)] Evidence for dose response and large size effect from individual studies (see Table 4)	Three papers [105, 107, 108] Quality of body of evidence assessed using GRADE method
SACN [40]. (Grey literature) AMSTAR Rating: Moderate
To review the evidence in respect to dietary carbohydrates and oral health	Peer-reviewed PCS and RCT studies in humans. Exposure all categories of dietary CHO including sugars as amount, frequency or dietary sources. Studies to have data to enable HR, RR or OR and measure of uncertainty (CI, SD or P value). Clinical assessment of caries. DMFT/dmft, DMFS/dmfs, RCI, visible caries with dentine involvement	UK, USA (WHO regions: European, The Americas)	Narrative account of included studies. Two included studies with data on a quantified amount of sugars intake and dental caries in permanent dentition (see Table 4)	Three papers [106–108] Quality of studies not assessed
Mahboobi et al. [41] AMSTAR Rating: Moderate
To assess the association between free sugars and dental caries (incidence and prevalence) in 6- to 12-year-old children from longitudinal evidence	January 1, 2004 and September 22, 2019 Cohort studies only Children 6–12 years only	Finland (WHO Region European)	Narrative report only. Two studies with relevant data to this review: Ruottinen et al. [109] Karjalainen et al. [110] (both positive association between sucrose and caries)	None reporting doses response
Turck et al. [12] AMSTAR Rating: Moderate
To deliver a Scientific Opinion UL for sugars based on available data on dental caries (and other diseases and metabolic endpoints). To identify data on dose–response relationship and/or level of intake at which the risk of dental caries is not increased	RCT, non-randomised trials, PCS	Finland, UK USA (WHO regions: European, The Americas)	Reported findings of individual studies (pooling of data across studies was not possible). Notes dose-responses in individual studies in adults [104] and children [106–108, 111] Table 4 New analysis of data from STRIP cohort study showed caries incidence at 6 years was ~ 4 × higher in the highest quartile of sucrose intake at aged 3 yrs. (mean sucrose intake 44 (range: 34.5 to 65.9) g/day) (~ 16 (12 to 24) % E) vs. lowest quartile (mean sucrose intake 15.9 (range: 7.4 to 20.9) g/day) (5.8 (2.6 to 7.6) % E), (OR: 4.32 (95% CI: 1.31, 14.25) Risk increased by 1.64 (95% CI: 1.13, 2.37) for each 10 g/day increase in sucrose intake at 3 years. NS when new caries was expressed as dmft increment Sucrose intake at 12 years and caries increment 12–16 years NS (low participant number) New analysis of data from Iowa Fluoride Study found no relationship between sugars intake over the study period and dental caries between the ages of 5 and 9 years (mixed dentition) after controlling for relevant confounders, Mean intake of sugars high: 114 g/day (range: 53 to 216 g/day)	Three studies (7 papers) with dose response data [104–108, 110, 111] RoB assessed using OHAT (see Table 4
Moores et al. [4] AMSTAR Rating: High
To report an update of the systematic review by Moynihan & Kelly [3] of data published 2011–2020 on amount of sugars consumption and dental caries in both adults and children	Epidemiological studies published since November 2011. Reviews with new data. Excluded theses, abstracts, and preprints Included intervention studies altering sugars in-group compared with control with different sugars, and which included information on caries, or comparisons of higher vs lower caries as an outcome. Timescale > / = 1 yr Observational studies reporting quantity of sugars or change in sugars and information on dental caries were included All timescales were included All countries All languages	Australia, Brazil, Denmark Finland, Japan, Kenya, Malaysia, Netherlands, Poland, Puerto Rico, Thailand UK, USA (WHO regions: African, European, SE Asian, Pan Pacific, The Americas)	Vote counting and Harvest Plots supported by narrative. 11/15 studies in children and 6/8 studies in adults reported at least one positive association between sugars and caries. Balance of data supported lower caries with sugars < 10% E and also < 5% E compared with > 5% E 5/7 studies reporting dose response found a positive relationship (adjusted analysis). 2/7 (both with serious RoB) reported no correlation in unadjusted bivariate analysis (unadjusted) see Table 4 for details	Seven studies with doses response data [104, 112–117] Quality of studies assessed using OHAT (see Table 4)

CHO Carbohydrate, CI Confidence interval, DMFT/dmft Decayed missing and filled teeth permanent/primary, DMFS/dmfs Decayed missing and filled tooth surfaces permanent/primary, HR Hazards ratio, OR Odds ratio, UL Tolerable Upper Level, RCI Root caries index, RCTs Randomised controlled trials, RR Relative risk, SACN Scientific Advisory Committee on Nutrition (UK), SD Standard deviation, SMD Standard mean difference, WHO World Health Organization

^a Review Question 3: What are the effects of decreasing sugars consumption on levels of dental caries?

^b See Table 4 for details of studies