Peroxisome proliferator-activated receptor (PPAR) γ polymorphism, vitamin D, bone mineral density and periodontitis in postmenopausal women

Could Vitamin D influence risk for Periodontal Disease - to "D" or not to "D"?

PURPOSE OF REVIEW

The purpose of this review is to discuss the literature on associations between vitamin D and periodontal disease, including its strengths and weaknesses. Future direction for continued work in this area is provided.

RECENT FINDINGS

Research in cross-sectional cohorts, surveys, and case-control studies provide support for a role of vitamin D in periodontal disease, especially using clinical indicators such as bleeding on probing and clinical attachment loss. However, these studies have a number of limitations. They cannot establish temporality of these associations. Most case-control studies have been limited in sample size and have inconsistent findings. A number of cross-sectional studies are restricted to select populations (e.g., persons with HIV, diabetes, rheumatoid arthritis) limiting extrapolation of findings to the general aging population.Fewer prospective studies have been conducted, and only three have examined associations using a biomarker for vitamin D that reflects exposure from all its sources (sunlight, diet and supplements). One study is limited by using self-reported measures of disease outcomes, and only two used measures of alveolar crestal height. However, of the prospective studies published, there is a suggestion that vitamin D might prevent against tooth loss. Only two randomized controlled trials have examined these associations, and they support the effects of vitamin D supplementation on prevention of tooth loss and gingival bleeding.

SUMMARY

We strongly suggest that new research should focus on prospective study designs with followup of participants longer than a decade and long-term clinical trials. Such studies should incorporate measures of alveolar bone loss and tooth loss with indication for reason for tooth loss. Such clinical trials should be designed to examine both the influence of vitamin D supplementation alone as well as with other nutrients (e.g., calcium) or therapeutic medications (e.g., bisphosphonates). Currently, there is no strong evidence to suggest that vitamin D protects against development of periodontal disease.

MAEA rs6815464 polymorphism and periodontitis in postmenopausal Japanese females: A cross-sectional study

OBJECTIVES

Macrophage erythroblast attacher (MAEA) is a membrane protein that regulates the development of mature macrophages by mediating attachment with erythroblasts. A polymorphism rs6815464 (C/G) in MAEA gene was reported to be associated with type II diabetes. Along with diabetes, osteoporosis shows an increased prevalence in postmenopausal females, and both diseases have been reported to be associated with periodontitis. Therefore, we explored the relevance of the MAEA polymorphism to periodontitis, bone mineral density (BMD) and haemoglobin A1c (HbA1c).

DESIGN

This was a cross-sectional study with the final sample comprised of 344 postmenopausal Japanese females. Probing pocket depth (PPD) and clinical attachment level (CAL) were measured. Genotype was determined by TaqMan assay. Blood biochemical parameters and BMD of the lumbar spine were evaluated.

RESULTS

No differences were found in age, body mass index, HbA1c, BMD, number of teeth, bone metabolism parameters between the genotypes. Mean CAL and percentage of sites with PPD or CAL ≥ 5 mm were higher in the G-allele carriers than in the non-carriers. Multiple logistic regression analyses revealed that G-allele carriage was associated with severe periodontitis (odds ratio = 3.73, 95% CI = 1.36-10.19).

CONCLUSION

Our results suggested that the MAEA gene polymorphism was independently associated with severe periodontitis.

Vitamin D levels and risk for periodontal disease: A systematic review

OBJECTIVE

To evaluate the existing evidence supporting or refuting the following questions: (i) Do patients with lower vitamin D levels have higher risk for periodontal disease? (ii) Are periodontal treatment outcomes improved by the adjuvant supplementation of vitamin D or by elevated serum vitamin D levels?

MATERIAL AND METHODS

MEDLINE, SCOPUS, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched up to September 2017. Studies were included if they had measured serum vitamin D levels or vitamin D intake and any periodontal parameter.

RESULTS

Overall, 27 studies were included (13 cross-sectional studies, 6 case-control studies, 5 cohort studies, 2 randomized clinical trials and 1 case series study). Sixty-five percent of the cross-sectional studies reported significant associations between low vitamin D levels and poor periodontal parameters. None of the observational longitudinal studies found that periodontal disease progression could be attributed to lower vitamin D levels. No interventional studies that evaluated the use of vitamin D supplementation as a solely adjuvant to periodontal treatment was found. No meta-analysis was performed due to high variability across studies.

CONCLUSION

The data to support or refute the association between vitamin D levels and periodontal disease are inconclusive at the moment. More rigorously designed longitudinal studies with standardized definitions of periodontal disease and vitamin D are necessary.

Influence of the Periodontal Disease, the Most Prevalent Inflammatory Event, in Peroxisome Proliferator-Activated Receptors Linking Nutrition and Energy Metabolism

Periodontal disease is considered one of the main pathologic diseases occurring in humans. Its pathologic process involves inflammatory reactions producing periodontal bone resorption and the tooth loss. But some patients do not present an evident clinical inflammation with bone resorption, and in others, the inflammation is prominent without bone resorption. A key question could be to investigate a different way of responding to aggression. Inflammation requires a complex intracellular metabolic process, starting with the harmful recognition and activation of the inflammasome, continues the energy supply with the alteration of oxidative stress conditions, and finishes with the elimination of the aggression with autophagy/apoptosis mechanisms, then concludes with recovery. Peroxisome proliferator-activated receptors (PPARs) are essential molecules produced in inflammation, and its genes and its activation have been related to periodontal disease. Also, an important aspect is the influence of PPARs in bone metabolism; the main periodontitis symptom is bone loss and PPARγ activation that can downregulate the bone resorption in experimental periodontitis, PPARγ-coated titanium dental implant surfaces could carry the antiinflammatory gene and restrain inflammation. PPARs could be one of the meeting background points with atherosclerosis/cardiovascular disease, diabetes and metabolic syndrome showing a modified proinflammatory statement such as it is described in periodontitis.

Association between periodontal disease and osteoporosis by gender: a nationwide population-based cohort study

Periodontitis and osteoporosis are primary concerns in public health and clinical management. The aim of this study was to investigate the association between periodontitis and osteoporosis by gender.Data were retrieved from the National Health Insurance Research Database, Taiwan. A diagnosis of periodontitis was defined on the basis of subgingival curettage, periodontal flap operation, and gingivectomy (excluding those with restorative or aesthetic indications). Multiple logistic regression was used for analysis. After adjusting for age, sex, income, and geographical region, there was a significant association between periodontitis and osteoporosis among women (odds ratio: 1.96; 95% confidence interval 1.17-3.26). The association between periodontitis and osteoporosis was significant among women.

PPARγ gene polymorphism, C-reactive protein level, BMI and periodontitis in post-menopausal Japanese women

BACKGROUND

Several studies have reported inconsistent results regarding the association between the PPARγPro12Ala polymorphism and obesity. Obese individuals had higher C-reactive protein (CRP) levels compared with those of normal weight, and PPARγ activation could significantly reduce serum high-sensitive CRP level. We have previously suggested that the Pro12Ala polymorphism represents a susceptibility factor for periodontitis, which is a known risk factor for increased CRP level.

OBJECTIVES

The aim was to investigate associations between PPARγ gene polymorphism, serum CRP level, BMI and/or periodontitis among post-menopausal Japanese women.

MATERIALS AND METHODS

The final sample in this study comprised 359 post-menopausal Japanese women. Periodontal parameters, including PD, CAL and BOP, were measured per tooth. PPARγPro12Ala genotype was determined by PCR-RFLP. Hs-CRP value was measured by a latex nephelometry assay.

RESULTS

No significant differences in age, BMI or periodontal parameters were found between the genotypes. The percentages of sites with PD ≥ 4 mm were significantly higher among the hsCRP ≥ 1 mg/l group than the hsCRP < 1 mg/l group (p = 0.003). Positive correlations were found between serum hsCRP levels and the percentages of sites with PD ≥ 4 mm (p = 0.043) in PPARγ Ala allele carriers, and BMI (p = 0.033) in non-carriers. After adjustment for model covariates, BMI was significantly associated with serum hsCRP level.

CONCLUSION

The PPARγPro12Ala polymorphism was not independently associated with periodontitis, serum CRP level or BMI in post-menopausal Japanese women. However, serum hsCRP level correlated with periodontitis in Ala allele carriers, and with BMI in non-carriers.