Shared social mechanisms underlying the risk of nine cancers: A life course study.

Identifying life periods during which social conditions have the highest impact on risk of common cancers in a population may help to reveal their underlying shared social mechanisms. We used the life course framework to estimate the extent to which life course SEP is associated with risk of nine cancers. In addition, we tested whether these associations conform to a critical period or cumulative life course model. Data were from a population-based case-control study of occupational exposures and cancer conducted in Montreal, Canada. Participants were males aged 35-70 years (n = 2,547) residing in the Montreal metropolitan area with primary, histologically confirmed cancers diagnosed between 1979 and 1985. Population controls (n = 512) were sampled from electoral lists. SEP was measured at three different periods of life based on respondent's report: during childhood, young adulthood and mid-life. We used a structured modeling approach using a series of unconditional logistic regressions to test which models best fit the data. Life course SEP increased the risk of all cancers. SEP in childhood was identified as a critical period for prostate and all gastrointestinal tract cancers except for esophagus cancer. In addition, the accumulation model best explained the data for melanoma and lung squamous cell carcinoma. Our findings suggest that childhood social circumstances are a common risk factor for several cancers among men; our results provide insights into the mechanisms involved in the etiology of nine cancers.

Efficacy of metformin in the management of periodontitis: A systematic review and meta-analysis.

Periodontitis is characterized by inflammation of the periodontium and leads to loss of teeth if untreated. Although a number of surgical and pharmacological options are available for the management of periodontitis, it still affects a large proportion of population. Recently, metformin (MF), an oral hypoglycemic, has been used to treat periodontitis. The aim of this review is to systematically evaluate the efficacy of MF in the treatment of periodontitis. An electronic search was carried out using the keywords 'metformin', 'periodontal' and 'periodontitis' via the PubMed/Medline, ISI Web of Science and Google Scholar databases for relevant articles published from 1949 to 2016. The addressed focused question was: 'Is metformin effective in reducing bone loss in periodontitis? Critical review and meta-analysis were conducted of the results obtained in the selected studies. Following the removal of the duplicate results, the primary search resulted in 17 articles and seven articles were excluded based on title and abstract. Hence, 10 articles were read completely for eligibility. After exclusion of four irrelevant studies, six articles were included. The topical application of MF resulted in improved histological, clinical and radiographic outcomes. Additionally, results from the meta-analysis indicated that application of metformin improved the clinical and radiographic outcomes of scaling and root-planing, but at the same time heterogeneity was evident among the results. However, because of a lack of histological and bacterial studies, in addition to short follow-up periods and risk of bias, the long-term efficacy of MF in the treatment of bony defects is not yet ascertained. Further studies are needed to envisage the long-term efficacy of MF in the management of periodontitis.

Periodontal diseases and risk of oral cancer in Southern India: Results from the HeNCe Life study.

Some studies suggest that periodontal diseases increase the risk of oral cancer, but contradictory results also exist. Inadequate control of confounders, including life course exposures, may have influenced prior findings. We estimate the extent to which high levels of periodontal diseases, measured by gingival inflammation and recession, are associated with oral cancer risk using a comprehensive subset of potential confounders and applying a stringent adjustment approach. In a hospital-based case-control study, incident oral cancer cases (N = 350) were recruited from two major referral hospitals in Kerala, South India, from 2008 to 2012. Controls (N = 371), frequency-matched by age and sex, were recruited from clinics at the same hospitals. Structured interviews collected information on several domains of exposure via a detailed life course questionnaire. Periodontal diseases, as measured by gingival inflammation and gingival recession, were evaluated visually by qualified dentists following a detailed protocol. The relationship between periodontal diseases and oral cancer risk was assessed by unconditional logistic regression using a stringent empirical selection of potential confounders corresponding to a 1% change-in-estimates. Generalized gingival recession was significantly associated with oral cancer risk (Odds Ratio = 1.83, 95% Confidence Interval: 1.10-3.04). No significant association was observed between gingival inflammation and oral cancer. Our findings support the hypothesis that high levels of periodontal diseases increase the risk of oral cancer.

The dental COVID-19 paradox: Disparity in behaviors inside and outside dental schools in Canada.

OBJECTIVE: To describe the personal and professional behavior and assess the perceptions of protection and fear of contracting coronavirus disease 2019 (COVID-19) among faculty, staff, and students from all 10 Canadian dental schools during the second year of the pandemic. METHOD: Participants from a Pan-Canadian prospective study answered monthly questionnaires about their activities between April 2021 and March 2022. In May 2022, additional questions were asked about their perception of protection, fear of infection, and instances of COVID-19 testing. RESULTS: Six hundred participants were initially recruited. Over time, the participants spent less time at home and increased their participation in indoor social activities, a trend influenced by the fluctuations in COVID-19 cases (ß = â€’0.02). Over 90% of the participants were fully vaccinated, which decreased their fear of contracting the virus (χ2[4, 241‒243] = 196.07, p < 0.0001). Yet, their attitude toward protective measures did not change, and they followed them within school. CONCLUSIONS: This work shows a paradoxical behavior among dental students, staff, and faculty members in Canadian dental schools. While factors such as the vaccine's limited efficacy and a desire to protect others may contribute to stringent protective behaviors within dental schools, the mandatory nature of these measures was likely the primary motivator for the compliance. Despite potential efforts to minimize exposure to the virus during risk periods and the frequent COVID-19 testing, this paradoxical behavior raises questions about professional responsibilities extending beyond the workplace. Thus, dental schools should incorporate education about the rationale behind following different protocols and the potential consequences of outside school behaviors.

Lung Cancer Pre-Diagnostic Pathways from First Presentation to Specialist Referral.

BACKGROUND: Lung cancer is often diagnosed at a late stage with high associated mortality. Timely diagnosis depends on timely referral to a respiratory specialist; however, in Canada, little is known about how patients move through primary care to get to a respiratory specialist. Accordingly, we aimed to identify and describe lung cancer pre-diagnostic pathways in primary care from first presentation to referral. METHODS: In this retrospective cohort study, patients with primary lung cancer were recruited using consecutive sampling (n = 50) from a lung cancer center in Montréal, Québec. Data on healthcare service utilization in primary care were collected from chart reviews and structured patient interviews and analyzed using latent class analysis to identify groups of patients with similar pre-diagnostic pathways. Each group was described based on patient- and tumor-related characteristics and the sequence of utilization activities. RESULTS: 68% of the patients followed a pathway where family physician (FP) visits were dominant ("FP-centric") and 32% followed a pathway where walk-in clinic and emergency department (ED) visits were dominant ("ED-centric"). Time to referral in the FP group was double that of the ED group (45 days (IQR: 12-111) vs. 22 (IQR: 5-69)) with more advanced disease (65% vs. 50%). In the FP group, 29% of the patients saw their FP three times or more before being referred and 41% had an ED visit. CONCLUSIONS: Our findings may reflect the challenge of diagnosing lung cancer in primary care, missed opportunities for earlier diagnosis, and a lack of integration between primary and specialist care.

Acetylcholinesterase inhibitors and risk of bleeding and acute ischemic events in non-hypertensive Alzheimer's patients.

INTRODUCTION: Acetylcholinesterase inhibitors (AChEIs) are commonly used to treat mild to moderate cases of Alzheimer disease (AD). To the best of our knowledge, there has been no study estimating the risk of bleeding and cardiovascular events in patients with non-hypertensive AD. Therefore, this study aimed to estimate the association between AChEIs and the risk of bleeding and cardiovascular ischemic events in patients with non-hypertensive AD. METHODS: A nested case-control study was conducted to estimate the risk of bleeding and ischemic events (angina, myocardial infarction [MI], and stroke) in patients with AD. This study was conducted using the UK Clinical Practice Research Datalink and Hospital Episode Statistics (HES) databases. The study cohort consisted of AD patients ≥65 years of age. The case groups included all AD subjects in the database who had a bleeding or ischemic event during the cohort follow-up. Four controls were selected for each case. Patients were classified as current users or past users based on a 60-day threshold of consuming the drug. Simple and multivariable conditional logistic regression analyses were used to calculate the adjusted odds ratio for bleeding events and cardiovascular events. RESULTS: We identified 507 cases and selected 2028 controls for the bleeding event cohort and 555 cases and 2220 controls for the ischemic event cohort. The adjusted odds ratio (OR) (95% confidence interval [CI]) for the association of AChEI use was 0.93 (0.75 to 1.16) for bleeding events, 2.58 (1.01 to 6.59) for angina, and 1.89 (1.07 to 3.33) for MI. Past users of AChEIs were also at increased risk of stroke (1.51 [1.00 to 2.27]). DISCUSSION: This is the first study assessing the risk of bleeding and cardiovascular events in patients with non-hypertensive AD. Our findings could be of great interest for clinicians and researchers working on AD.

Malocclusion traits and oral health-related quality of life in children with osteogenesis imperfecta: A cross-sectional study.

BACKGROUND: The incidence of malocclusion is higher among people with osteogenesis imperfecta (OI) than the general population, and treatment options are limited due to the weak structure of bones and teeth. Focusing on those malocclusion traits that might have a high impact on a patient's oral health-related quality of life (OHRQoL) is warranted. METHODS: A total of 138 children and adolescents with OI were examined for malocclusion traits. OHRQoL was measured using age-specific versions (8 through 10 years and 11 through 14 years) of the Child Perceptions Questionnaire (CPQ), considering the following domains: oral symptoms, functional limitation, emotional well-being, and social well-being. Higher scores implied worse OHRQoL. Multivariable ordinal logistic regression was used to estimate the association between malocclusion traits and OHRQoL. RESULTS: Among children aged 8 through 10 years (n = 56), the CPQ and its constituent domain scores were relatively similar between those with malocclusion (higher scores) and those without. In the adolescent (n = 82) group aged 11 through 14 years; however, those with posterior crossbite (odds ratio, 5.01; 95% confidence interval, 1.40 to 12.41) or open bite (odds ratio, 3.21; 95% confidence interval, 1.21 to 10.23) experienced statistically significantly higher degrees of functional limitations (a higher functional limitation score) than those without. CONCLUSIONS: Adolescents with OI and posterior open bites or crossbites have substantial self-reported functional limitations and worse oral symptoms, which warrants additional investigation and therapeutic trials in an attempt to improve the malocclusion. In addition, the authors found that the CPQ can be a useful tool in a clinical trial of orthodontic interventions in OI.

Increased risk of oropharyngeal cancers mediated by oral human papillomavirus infection: Results from a Canadian study.

BACKGROUND: This study aimed to estimate the extent to which oral sex behavior is associated with an increased risk of oropharyngeal cancers (OPCs), and how much of the association is mediated by oral human papillomavirus (HPV) infection. METHODS: We used data from a hospital-based case-control study conducted in Montreal, Canada. Information on oral sex behaviors was collected. Oral rinse and oral brush specimens were analyzed for HPV positivity and genotyping. Logistic regression estimated the odds ratios (OR) and 95% confidence intervals (CI) for the association between oral sex behaviors and OPC. RESULTS: Onset of oral sex practice at age 16 years or younger had an increased risk of OPCs relative to those with onset after age 30 years (OR = 2.98; 95% CI 1.37-6.47). This association decreased (OR = 1.09; 95% CI 0.25-4.71) when restricted to those positive for HPV. CONCLUSIONS: Our results suggest that the association between oral sex and OPC seems mediated by oral HPV infection.

Human papillomavirus genotypes and risk of head and neck cancers: Results from the HeNCe Life case-control study.

OBJECTIVE: Human papillomaviruses (HPV) are changing dramatically the epidemiologic landscape of head and neck cancers (HNCs). Their role in the aetiology of these cancers varies widely among HNCs subsites, sex and geographical regions worldwide. We describe HPV prevalence and its association with HNCs risk overall and by anatomical subsite in a sample of Canadians. MATERIALS AND METHODS: The HeNCe Life study recruited 460 incident HNCs cases and 458 controls frequency-matched by age and sex from four Montreal hospitals in 2005-2013. We tested oral rinse and oral brush specimens for mucosal HPV genotypes. HPV positivity was categorized hierarchically as either negative, exclusively non-α-9 species types, α-9 types other than HPV16, and HPV16. We estimated odds ratios (OR) and 95% confidence intervals (CI) for the associations between HPV and HNCs using unconditional logistic regression, controlling for confounders. RESULTS: The prevalence of HPV infection among controls and cases was 14.5% and 41.2% in oral rinse and 3.1% and 24.4% in oral brush samples, respectively. HPV16 was the predominant genotype with an oral rinse and oral brush prevalence of 26.3% and 16.2% among cases and 2.4% and 0.2% among controls, respectively. HPV infection was associated with an increased risk of HNCs overall (OR=4.18; 95% CI, 2.94-5.95) and oropharyngeal cancer only (OR=10.3; 95% CI, 6.8-15.7). HNCs and oropharyngeal cancer were strongly associated with HPV16 (OR=18.1; 95% CI, 9.1-35.8, and OR=47.2; 95% CI, 23.1-96.6, respectively). CONCLUSION: HPV infection, particularly HPV16, was associated with an increased HNCs risk, most strongly for oropharyngeal cancers.

Nonlinear association between betel quid chewing and oral cancer: Implications for prevention.

PURPOSE: Betel quid chewing is a major oral cancer risk factor and the human papillomaviruses (HPV) may play an aetiological role in these cancers. However, little is known about the shape of the dose-response relationship between the betel quid chewing habit and oral cancer risk in populations without HPV. We estimate the shape of this dose-response relationship, and discuss implications for prevention. METHODS: Cases with oral squamous cell carcinoma (350) and non-cancer controls (371) were recruited from two major teaching hospitals in South India. Information on socio-demographic and behavioral factors was collected using a questionnaire and the life grid technique. The effect of daily amount of use and duration of the habit were estimated jointly as risk associated with cumulative exposure (chew-years). The shape of the dose-response curve was estimated using restricted cubic spline transformation of chew-years in a conditional logistic regression model. Risk estimates for low dose combinations of daily amount and duration of the habit were computed from flexible regression. RESULTS: Most (72%) oral cancer cases were betel quid chewers in contrast to only 18% of controls. A nonlinear dose-response relationship was observed; the risk increased steeply at low doses and plateaued at high exposures to betel quid (>425 chew-years). A threefold increase in risk (OR=3.92, 95%CI: 1.87-8.21) was observed for the lowest dose; equivalent to the use of one quid per day for one year. CONCLUSION: Our findings may be used to counsel people to refrain from even low betel quid chewing.