Periodontal disease as one possible explanation for the Mexican paradox

Periodontology and pregnancy: An overview of biomedical and epidemiological evidence

Women are particularly susceptible to developing gingival problems during pregnancy. In addition, periodontal disease in pregnant women may lead to adverse outcomes for both mother and infant, which have serious clinical and public health implications. Both scenarios have been extensively researched, helping to bring attention to pregnant women as an important and vulnerable population as it concerns periodontal health. The increase in gingival inflammation caused by hormonal changes in pregnant women is undisputed and has been studied and documented since the 1960s, although the exact etiology is not fully understood. The relationship between periodontal disease during pregnancy and adverse pregnancy outcomes is less substantiated, because of conflicting evidence. This review of the biomedical and epidemiologic literature provides an overview of both sides of this relationship and examines the potential mechanisms for developing periodontal disease during pregnancy and the proposed mechanisms by which periodontal disease leads to adverse pregnancy outcomes.

Prevalence and risk factors of periodontal disease among pre-conception Chinese women

BACKGROUND

Periodontal disease is one of the most common chronic infectious diseases. It has been reported that periodontal disease is associated with various adverse pregnancy outcomes including preterm birth, low birth weight, and gestational diabetes mellitus. Given the fact that the treatment for periodontal disease during pregnancy was ineffective in improving pregnancy outcomes by most of studies, the pre-conception period has been put forward as a more optimal time. However, very few studies have reported the prevalence of periodontal disease among pre-conception women. This study aimed to examine the prevalence and risk factors of periodontal disease among Chinese pre-conception women.

METHODS

A survey was conducted among pre-conception women at the Maternal and Child Health Hospital, Changzhou, China between January 2012 and December 2014. A total of 987 pre-conception women were recruited for a full-mouth dental examination after providing informed consent. A dental examination was carried out by probing six sites per tooth using a manual UNC-15 probe and a recording form.

RESULTS

The overall rate of periodontal disease among participants was 73.9% (729/987) (95% confidence interval (CI): 71.0-76.6%). Among women with periodontal disease, 48.0% of cases were mild, 50.9% were moderate and 1.1% were severe. Self-reported bleeding during tooth brushing was the only significant predictive factor for overall periodontal disease (adjusted odds ratio (aOR): 3.71, 95% CI: 2.24, 6.15, P < 0.001) and moderate/severe periodontal disease (aOR: 5.17, 95% CI: 3.05, 8.79, P < 0.001).

CONCLUSION

A high prevalence of periodontal disease was found in pre-conception Chinese women. Women who have bleeding during tooth brushing could be at increased risk of periodontal disease, and might require further oral health care.

Association between maternal periodontal disease and preterm delivery and low birth weight

OBJECTIVE

It has been suggested that periodontal disease is an important risk factor for preterm low birth weight (PLBW). The purpose of this study was to determine the association of maternal periodontitis with low birth weight (LBW) and preterm birth (PB).

MATERIALS AND METHODS

Pregnant women (n = 211) aged 22-40 years were enrolled while receiving prenatal care. Dental plaque, probing depth, bleeding on probing, and clinical attachment level were used as criteria to classify three groups: a healthy group (HG; n = 82), a gingivitis group (GG; n = 67), and a periodontitis group (PG; n = 62). At delivery, birth weight was recorded.

RESULTS

Mean infant weight at delivery was 3084.9 g. The total incidence of preterm birth and LBW infants was 10.4% and 8.1%, respectively. The incidence of LBW infants was 4.2% for term and 40.9% for preterm gestations. Maternal height was not correlated with infant birth weight (p = 0.245). Significant differences in mean infant birth weight were observed among the HG, GG, and PG groups (p = 0.030). No significant relationship was found between periodontal disease and PB, but the association between periodontal disease and LBW was significant.

CONCLUSION

After appropriately controlling for confounding variables, our results do not support the hypothesis of an association that was observed in previous studies of maternal periodontal disease and infant PB, but the association between periodontal disease and LBW is significant.

Racial and ethnic disparities in preterm births in infants conceived by in vitro fertilization in the United States

OBJECTIVE

The objective of the study was to examine racial and ethnic differences in preterm births in infants conceived by in vitro fertilization (IVF).

STUDY DESIGN

A retrospective cohort study was conducted of 97,288 singleton and 40,961 twin pregnancies resulting from fresh, nondonor IVF cycles using 2006-2010 data from the Society for Assisted Reproductive Technology Clinic Online Reporting System.

RESULTS

Rates of very early preterm (<28 weeks), early preterm (<32 weeks), and preterm birth (<37 completed weeks) varied across racial and ethnic groups in both singleton and twin pregnancies. In singletons, with white women as the referent, after adjustment of confounding variables, the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of very early preterm birth, early preterm birth, and preterm birth in black women were 4.8 (95% CI, 4.1-5.7), 3.9 (95% CI, 3.4-4.4), and 2.1 (95% CI, 1.9-2.3). Hispanic women had a significantly lower rate of preterm births as compared with black women and similar or slightly higher rates as compared with white women. Native American women were not at an increased risk of any types of preterm births; Asian women were at a reduced risk of preterm twin births (adjusted OR, 0.8; 95% CI, 0.7-0.9).

CONCLUSION

There exist notable racial and ethnic disparities in preterm births in infants conceived by IVF, suggesting that mechanisms other than socioeconomic disparities contribute to this difference.

Relationship between periodontal diseases and preterm birth: recent epidemiological and biological data

For ten years, the incidence of preterm birth does not decrease in developed countries despite the promotion of public health programs. Many risk factors have been identified including ethnicity, age, tobacco, and infection. However, almost 50% of preterm birth causes remain unknown. The periodontal diseases are highly prevalent inflammatory and infectious diseases of tooth supporting tissues leading to an oral disability. They influence negatively general health worsening cardiovascular diseases and diabetes. Periodontal diseases have been also suspected to increase the rate of preterm birth, but data remain contradictory. The objective of this review is to present the principal results of epidemiological, biological, and interventional studies on the link between periodontal diseases and preterm birth. The conclusions of this work underline the importance for the physician/obstetrician to identify women at risk for preterm birth and to address these patients to dentist for periodontal examination and treatment in order to limit adverse pregnancy outcomes.

A book of ideas collected from Medical Hypotheses: Death can be cured by Roger Dobson

A new collection of ideas from Medical Hypotheses by Roger Dobson is entitled Death can be cured and 99 other Medical Hypotheses. It consists of humorous summaries of Medical Hypotheses articles from the past 30 years. The book's humour derives mainly from the subject matter, although sometimes also from the 'unconventional' approach of the authors with respect to matters such as evidence, argument or inference. Medical Hypotheses has generated such a lot of apparently- or actually-bizarre ideas because it aims to be open to potentially revolutionary science. The journal's official stance is that more harm is done by a failure to publish one idea that might have been true, than by publishing a dozen ideas that turn out to be false. Bizarre ideas tend to catch attention, and may stimulate a valuable response--even when a paper is mostly-wrong. A paper may be flawed but still contain the germ of an idea that can be elaborated and developed. The journal review process is susceptible to both false positives and false negatives. False positives occur when we publish an idea that is wrong; false negatives occur when we fail to publish an important idea that is right, and a potential scientific breakthrough never happens. False positives are more obvious, since the paper will be ignored, refuted, or fail to be replicated--and often attracts criticism and controversy. Editors may therefore take the more cautious path of avoiding false positives more assiduously than false negatives; however, this policy progressively favours less-ambitious science. Consequently, in Medical Hypotheses the 'set point' of risk is nearer to the false positive end of the spectrum than for most journals - and the publication of many apparently-bizarre papers is a natural consequence of this policy.

Periodontal disease and pregnancy outcomes: state-of-the-science

To examine the existing evidence on the relationship between periodontal disease and adverse pregnancy outcomes, we conducted a systematic review of studies published up to December 2006. Studies published in full text were identified by searching computerized databases (e.g., MEDLINE, EMBASE). A meta-analysis was performed to pool the effect size of the clinical trials. Forty-four studies were identified (26 case-control studies, 13 cohort studies, and 5 controlled trials). The studies focused on preterm low birth weight, low birth weight, preterm birth, birth weight by gestational age, miscarriage or pregnancy loss, preeclampsia, and gestational diabetes mellitus. Of the chosen studies, 29 suggested an association between periodontal disease and increased risk of adverse pregnancy outcome (odds ratios [ORs] ranging from 1.10 to 20.0) and 15 found no evidence of an association (ORs ranging from 0.78 to 2.54). A meta-analysis of the clinical trials suggested that oral prophylaxis and periodontal treatment may reduce the rate of preterm low birth weight (pooled risk ratio (RR): 0.53, 95% confidence interval [CI]: 0.30-0.95, P < 0.05), but did not significantly reduce the rates of preterm birth (pooled RR: 0.79, 95% CI: 0.55-1.11, P > 0.05) or low birth weight (pooled RR: 0.86, 95% CI: 0.58%1.29, P > 0.05). The authors conclude that periodontal disease may be associated with increased risk of adverse pregnancy outcomes. More methodologically rigorous studies are needed in this field. Currently, there is insufficient evidence to support the provision of periodontal treatment during pregnancy for the purpose of reducing adverse pregnancy outcomes.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to state that the published literature is not vigorous to clinically link periodontal disease and/or its treatment to specific adverse pregnancy outcomes, and explain that more rigorous studies with world-wide agreed-upon definitions are particularly needed before periodontal disease treatment can be recommended.