Table 3.

Systematic reviews and meta-analysis included in the review.

Sl. No	Author/Year/Country	Number of Studies	Study Period	Major Observations
1	Chaffee and Weston 2010 [5] USA	57	Up to 2010	In total, 41 studies suggested a positive association consistent with a biologically plausible role for obesity in the development of periodontal disease. The fixed-effects summary odds ratio was 1.35, with some evidence of a stronger association among younger adults, women, and non-smokers. Also, a greater mean CAL among obese individuals, a higher mean BMI among periodontal patients, and a trend of increasing odds of prevalent periodontal disease with increasing BMI.
2	Suvan et al. 2011 [10] U.K.	33	Up to 2009	There were 19 studies included in the meta-analyses. Statistically significant associations between periodontitis and BMI category obese OR 1.81(1.42, 2.30), overweight OR 1.27(1.06, 1.51), and obese and overweight combined OR 2.13(1.40, 3.26). Support an association between BMI overweight and obesity and periodontitis, although the magnitude is unclear.
3	Moura-Grec et al. 2014 [62] Brazil	31	Up to 2010	A positive association in 25 studies (not associated in 6 studies). The meta-analysis showed a significant association with obesity and periodontitis (OR = 1.30 [95% Confidence Interval (CI), 1.25–1.35]) and with mean BMI and periodontal disease (mean difference = 2.75). Obesity was associated with periodontitis, however, the risk factors that aggravate these diseases should be better clarified to elucidate the direction of this association.
4	Keller et al. 2015 [63] Denmark	13	Up to June 2014	Two longitudinal studies found a direct association between being overweight and the subsequent risk of developing periodontitis. Three studies found a direct association between obesity and the development of periodontitis among adults. Two intervention studies on the influence of obesity on periodontal treatment effects found that the response to non-surgical periodontal treatment was better among lean than obese patients. The remaining three studies did not report treatment differences between obese and lean participants. Among the eight longitudinal studies, one study adjusted for C-reactive protein (CRP), and biologic markers of inflammation such as CRP, interleukin-6, and tumor necrosis factor-α, and inflammation markers were analyzed separately in three of the five intervention studies. This systematic review suggests that overweight, obesity, weight gain, and increased waist circumference may be risk factors for the development of periodontitis or worsening of periodontal measures.
5	Nascimento et al. 2015 [64] Brazil	5	Up to Feb 2015	Subjects who became overweight and obese presented a higher risk of developing new cases of periodontitis (RR 1.13; 95%CI 1.06–1.20 and RR 1.33 95%CI 1.21–1.47 respectively) compared with counterparts who stayed at a normal weight. A clear positive association between weight gain and new cases of periodontitis was found. However, these results originated from limited evidence. Thus, more studies with prospective longitudinal designs are needed.
6	Papageorgiou et al. 2015 [65] Germany	15	Up to July 2013	No difference was found in clinical periodontal parameters, but significant differences in inflammatory or metabolic parameters were found between overweight/obese and normal-weight patients. Existing evidence is weak.
7	Martinez-Herrera et al. 2017 [9] Spain	28	2000-2017	A total of 26 studies described an association between obesity and periodontal disease (no association n = 2). The development of insulin resistance as a consequence of a chronic inflammatory state and oxidative stress could be implicated in the association between obesity and periodontitis.
8	Khan et al. 2018 [66] Australia	25	2003 and 2016	There were 25 eligible studies from 12 countries. 17 showed an association between obesity and periodontitis (odds ratios ranged from 1.1 to 4.5). The obesity indicators of BMI, waist circumference, waist-hip ratio, and body fat percentage were significantly associated with measures of periodontitis of bleeding on probing, plaque index, probing depths, clinical attachment loss, calculus, oral hygiene index, and community periodontal index. Two prospective cohort studies in the review showed no significant association between obesity and periodontitis, but these studies had limitations in study design and used inappropriate epidemiological diagnostic measures of periodontitis. Evidence suggests that obesity is associated with periodontitis in adolescents and young adults.
9	da Silva et al. 2021 [67] Brazil	92	upto Jan 2021	Ninety studies were included (cross-sectional/clinical trials [n = 82], case-control [n = 3], cohorts [n = 5]). Most of the studies demonstrated no significant difference in the measures of gingival inflammation regardless of the comparison performed. Meta-analysis showed that among individuals with periodontitis, significantly higher levels of gingival inflammation are observed in those with obesity (n of individuals = 240) when compared to those who were not obese (n of individuals = 574) (SMD:0.26; 95%CI:0.07–0.44). When considering population-based/those studies that did not provide periodontal diagnosis, significantly higher measures of gingival inflammation were observed in the groups with higher BMI.
10	Foratori-Junior et al. 2022 [68] Brazil	11	2000–2021	11 studies were included. Most studies had a low risk of bias. A positive association between overweight/obesity and periodontitis was found, with an average of 61.04% of women with overweight/obesity and periodontitis, showing the overall random-effects relative risk and 95% CI of 2.21 (1.53–3.17) (p < 0.001). A positive association was found between overweight/obesity and periodontitis during pregnancy.