Controversy of oral contraceptives and risk of rheumatoid arthritis: meta-analysis of conflicting studies and review of conflicting meta-analyses with special emphasis on analysis of heterogeneity

Lifestyle, Hormonal, and Metabolic Environmental Risks for Rheumatoid Arthritis

Although there is a substantial body of literature focused on understanding noninhalational risk-factors for rheumatoid arthritis, the data are mixed and often conflicting. Given the other health benefits for certain lifestyle modifications, it seems reasonable for clinicians to promote healthy lifestyle habits related to diet, exercise, maintenance of health weight, and maintenance of good dental hygiene. Overall, however, these lifestyle modifications may be expected to have modest benefit, and other strategies to prevent rheumatoid arthritis in high-risk patients are needed.

Global epidemiology of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease that predominantly affects the joints. The prevalence of RA varies globally, with generally a higher prevalence in industrialized countries, which may be explained by exposures to environmental risk factors, but also by genetic factors, differing demographics and under-reporting in other parts of the world. Over the past three decades, strong trends of the declining severity of RA probably reflect changes in treatment paradigms and overall better management of the disease. Other trends include increasing RA prevalence. Common risk factors for RA include both modifiable lifestyle-associated variables and non-modifiable features, such as genetics and sex. A better understanding of the natural history of RA, and of the factors that contribute to the development of RA in specific populations, might lead to the introduction of specific prevention strategies for this debilitating disease.

Association of Hormonal Contraceptive Use With Adverse Health Outcomes: An Umbrella Review of Meta-analyses of Randomized Clinical Trials and Cohort Studies

IMPORTANCE

Meta-analyses have reported conflicting data on the safety of hormonal contraception, but the quality of evidence for the associations between hormonal contraceptive use and adverse health outcomes has not been quantified in aggregate.

OBJECTIVE

To grade the evidence from meta-analyses of randomized clinical trials (RCTs) and cohort studies that assessed the associations between hormonal contraceptive use and adverse health outcomes among women.

DATA SOURCES

MEDLINE, Embase, and the Cochrane Database of Systematic Reviews were searched from database inception to August 2020. Search terms included hormonal contraception, contraceptive agents, progesterone, desogestrel, norethindrone, megestrol, algestone, norprogesterones, and levonorgestrel combined with terms such as systematic review or meta-analysis.

EVIDENCE REVIEW

The methodological quality of each meta-analysis was graded using the Assessment of Multiple Systematic Reviews, version 2, which rated quality as critically low, low, moderate, or high. The Grading of Recommendation, Assessment, Development and Evaluations approach was used to assess the certainty of evidence in meta-analyses of RCTs, with evidence graded as very low, low, moderate, or high. Evidence of associations from meta-analyses of cohort studies was ranked according to established criteria as nonsignificant, weak, suggestive, highly suggestive, or convincing.

RESULTS

A total of 2996 records were screened; of those, 310 full-text articles were assessed for eligibility, and 58 articles (13 meta-analyses of RCTs and 45 meta-analyses of cohort studies) were selected for evidence synthesis. Sixty associations were described in meta-analyses of RCTs, and 96 associations were described in meta-analyses of cohort studies. Among meta-analyses of RCTs, 14 of the 60 associations were nominally statistically significant (P ≤ .05); no associations between hormonal contraceptive use and adverse outcomes were supported by high-quality evidence. The association between the use of a levonorgestrel-releasing intrauterine system and reductions in endometrial polyps associated with tamoxifen use (odds ratio [OR], 0.22; 95% CI, 0.13-0.38) was graded as having high-quality evidence, and this evidence ranking was retained in the subgroup analysis. Among meta-analyses of cohort studies, 40 of the 96 associations were nominally statistically significant; however, no associations between hormonal contraceptive use and adverse outcomes were supported by convincing evidence in the primary and subgroup analyses. The risk of venous thromboembolism among those using vs not using oral contraception (OR, 2.42; 95% CI, 1.76-3.32) was initially supported by highly suggestive evidence, but this evidence was downgraded to weak in the sensitivity analysis.

CONCLUSIONS AND RELEVANCE

The results of this umbrella review supported preexisting understandings of the risks and benefits associated with hormonal contraceptive use. Overall, the associations between hormonal contraceptive use and cardiovascular risk, cancer risk, and other major adverse health outcomes were not supported by high-quality evidence.

Etiology and Risk Factors for Rheumatoid Arthritis: A State-of-the-Art Review

Rheumatoid arthritis (RA) is the most common systemic inflammatory rheumatic disease. It is associated with significant burden at the patient and societal level. Extensive efforts have been devoted to identifying a potential cause for the development of RA. Epidemiological studies have thoroughly investigated the association of several factors with the risk and course of RA. Although a precise etiology remains elusive, the current understanding is that RA is a multifactorial disease, wherein complex interactions between host and environmental factors determine the overall risk of disease susceptibility, persistence and severity. Risk factors related to the host that have been associated with RA development may be divided into genetic; epigenetic; hormonal, reproductive and neuroendocrine; and comorbid host factors. In turn, environmental risk factors include smoking and other airborne exposures; microbiota and infectious agents; diet; and socioeconomic factors. In the present narrative review, aimed at clinicians and researchers in the field of RA, we provide a state-of-the-art overview of the current knowledge on this topic, focusing on recent progresses that have improved our comprehension of disease risk and development.

Contraception in autoimmune diseases

Autoimmune diseases (AIDs) affect women and men with a 2:1 ratio, which suggests that hormonal contraceptives play a role in their clinical course. Combined oral contraceptives have complex, sometimes contradictory, effects on AIDs; they can worsen the situation in women with systemic lupus erythematosus and with anti-phospholipid syndrome, conditions in which they are contraindicated. Early studies indicated a positive effect on rheumatoid arthritis (RA), whereas more recent trials failed to do so, possibly because of the lowering of oestrogen content. Evidence of effects on multiple sclerosis (MS) is conflicting: risk may vary depending on the progestin used. Minor adverse effects may exist on inflammatory bowel diseases, and no significant effect was found on autoimmune thyroid diseases. Women can become sensitised to sex hormones. Progestin-only contraceptives may be used, although copper-releasing intra-uterine devices represent the best option. Finally, several organisations have issued guidelines for contraceptive use in women with AIDs.

Pregnancy, Periods, and "The Pill": Exploring the Reproductive Experiences of Women with Inflammatory Arthritis

Objective

Women with inflammatory arthritis appear to have fewer children as compared with healthy women, but few studies have assessed how patients' attitudes and decision making influence their family sizes. Little is also known about how patients experience other aspects of their reproductive lives, such as menstruation and contraception.

Methods

We partnered with ArthritisPower, a patient‐powered research network, and its associated online patient community, CreakyJoints, to create and disseminate a survey among female members aged 18‐50 years with inflammatory arthritis.

Results

Women in the final sample (n = 267) were 40 years old on average; most had rheumatoid arthritis (79%) and were predominantly white and college educated. Many women chose to limit childbearing because of their arthritis (58%); they feared that their arthritis was heritable, their diseases and medications could directly harm a fetus, they would be incapable of physically caring for a child, and arthritis could cause premature death, preventing them from raising their children. Infertility affected 40% of the sample. Half of women experienced subjective arthritis flares around the time of menstruation. Oral contraceptive pills (OCPs) did not worsen disease activity for most women and even prevented menstrual‐associated arthritis flares for a subset of women.

Conclusion

Our findings suggest that infertility, but also potentially outsized fear and anxiety related to their diagnoses, may affect the family sizes of women with inflammatory arthritis. The observation that menstruation worsens disease activity for some women requires additional study, and OCP use should be explored as a possible treatment for menstrual‐associated arthritis. Clinicians may wish to consider how they communicate patients' individual pregnancy‐associated risks, reassure patients when appropriate, and help to guide and support patients to make well‐informed reproductive decisions.

Models of suicide in elderly: a protocol for a systematic review

INTRODUCTION

The rates of suicide in the elderly population are generally higher than other age groups. Models of suicide that explain the phenomenon of suicide in later life may have research, clinical and educational implications for the field of ageing. The primary purpose of this systematic review is to identify and review existing models of suicide that have a particular focus on the elderly.

METHODS AND ANALYSIS

The authors intend reviewing the findings of observational studies including cohort studies, cross-sectional studies, case-control studies, and qualitative studies such as grounded theory designs which are published in Google Scholar, Scopus, PsycINFO, PubMed, Web of Science, Cochrane Database of Systematic Reviews and research-related journals. Models of suicide which specifically describe, explain and predict late life suicides will be included. Therapeutic, interventional and rehabilitation models, as well as models related to assisted suicide, will be excluded. The EndNote software will be employed for data management. Two independent reviewers will extract data. Methodological quality and the risk of bias of quantitative studies will be assessed using the Newcastle-Ottawa Scale and the Newcastle-Ottawa Scale adapted for cross-sectional studies, while that of qualitative studies will be assessed using the Critical Appraisal Skills Programme and the evaluative criteria of credibility, transferability, dependability and confirmability. The final report will present a range of models of suicide with a list of different subgroups.

ETHICS AND PUBLICATION

There are no predictable ethical issues related to this study. The findings will be published in prestigious journals and presented at international and national conferences.

PROSPERO REGISTRATION NUMBER

CRD42017070982.

Methods to systematically review and meta-analyse observational studies: a systematic scoping review of recommendations

Background

Systematic reviews and meta-analyses of observational studies are frequently performed, but no widely accepted guidance is available at present. We performed a systematic scoping review of published methodological recommendations on how to systematically review and meta-analyse observational studies.

Methods

We searched online databases and websites and contacted experts in the field to locate potentially eligible articles. We included articles that provided any type of recommendation on how to conduct systematic reviews and meta-analyses of observational studies. We extracted and summarised recommendations on pre-defined key items: protocol development, research question, search strategy, study eligibility, data extraction, dealing with different study designs, risk of bias assessment, publication bias, heterogeneity, statistical analysis. We summarised recommendations by key item, identifying areas of agreement and disagreement as well as areas where recommendations were missing or scarce.

Results

The searches identified 2461 articles of which 93 were eligible. Many recommendations for reviews and meta-analyses of observational studies were transferred from guidance developed for reviews and meta-analyses of RCTs. Although there was substantial agreement in some methodological areas there was also considerable disagreement on how evidence synthesis of observational studies should be conducted. Conflicting recommendations were seen on topics such as the inclusion of different study designs in systematic reviews and meta-analyses, the use of quality scales to assess the risk of bias, and the choice of model (e.g. fixed vs. random effects) for meta-analysis.

Conclusion

There is a need for sound methodological guidance on how to conduct systematic reviews and meta-analyses of observational studies, which critically considers areas in which there are conflicting recommendations.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0495-9) contains supplementary material, which is available to authorized users.

The role of female hormonal factors in the development of rheumatoid arthritis

RA is the most common chronic systemic autoimmune disease, with a higher prevalence in women, suggesting female hormonal factors play a role in the development of the disease. However, many controversies still exist. The aim of this review was to appraise data from recent research concerning female hormonal factors and their association with RA disease development. The study of female hormonal factors is challenging because serum levels may differ throughout a woman's lifetime and interact with various environmental, immunological, genetic and endocrine factors influencing the development of autoimmunity. As some female hormonal factors may be potentially modifiable, understanding their impact on RA development is clinically relevant and may result in specific preventive interventions in high-risk populations.

Environmental factors and hormones in the development of rheumatoid arthritis

The etiopathogenesis of rheumatoid arthritis (RA) is partially understood. Genetic, environmental, and hormonal factors and their interactions are considered to play an important role on disease development. The relative contribution of environmental factors to RA development is probably larger than previously thought. The aim of this review is to appraise robust evidence about the role of environmental and hormonal risk factors for RA. We will discuss inhaled pollutants, nutritional habits, infectious, hormonal, and reproductive factors. As some of these factors are potentially modifiable, understanding their impact on RA development opens new opportunities for potential interventions and disease prevention.

Comparison of two independent systematic reviews of trials of recombinant human bone morphogenetic protein-2 (rhBMP-2): the Yale Open Data Access Medtronic Project

BACKGROUND

It is uncertain whether the replication of systematic reviews, particularly those with the same objectives and resources, would employ similar methods and/or arrive at identical findings. We compared the results and conclusions of two concurrent systematic reviews undertaken by two independent research teams provided with the same objectives, resources, and individual participant-level data.

METHODS

Two centers in the USA and UK were each provided with participant-level data on 17 multi-site clinical trials of recombinant human bone morphogenetic protein-2 (rhBMP-2). The teams were blinded to each other's methods and findings until after publication. We conducted a retrospective structured comparison of the results of the two systematic reviews. The main outcome measures included (1) trial inclusion criteria; (2) statistical methods; (3) summary efficacy and risk estimates; and (4) conclusions.

RESULTS

The two research teams' meta-analyses inclusion criteria were broadly similar but differed slightly in trial inclusion and research methodology. They obtained similar results in summary estimates of most clinical outcomes and adverse events. Center A incorporated all trials into summary estimates of efficacy and harms, while Center B concentrated on analyses stratified by surgical approach. Center A found a statistically significant, but small, benefit whereas Center B reported no advantage. In the analysis of harms, neither showed an increased cancer risk at 48 months, although Center B reported a significant increase at 24 months. Conclusions reflected these differences in summary estimates of benefit balanced with small but potentially important risk of harm.

CONCLUSIONS

Two independent groups given the same research objectives, data, resources, funding, and time produced broad general agreement but differed in several areas. These differences, the importance of which is debatable, indicate the value of the availability of data to allow for more than a single approach and a single interpretation of the data.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42012002040 and CRD42012001907 .

Genetic and environmental risk factors for rheumatoid arthritis

Multiple genetic and environmental factors have been associated with an increased risk for rheumatoid arthritis (RA). Of these, the strongest associations have been seen with female sex, a family history of RA, the genetic factor the "shared epitope," and exposure to tobacco smoke. There is also renewed interest in mucosal inflammation and microbial factors as contributors to the development of RA. However, the identification of a "preclinical" period of RA that can be defined as local or systemic autoimmunity as measured by autoantibodies and other biomarkers prior to the development of clinically apparent synovitis suggests that the risk factors for RA are acting long prior to first clinical evidence of IA. As such, a major challenge to the field will be to investigate the full spectrum of the development of RA, from initiation and propagation of autoimmunity during preclinical RA and transition to clinically apparent synovitis and classifiable RA, to determine which genetic and environmental factors are important at each stage of disease development. Understanding the exact role and timing of action of risk factors for RA is especially important given the advent of prevention trials in RA, and the hope that a full understanding of genetic and environmental factors in RA could lead to effective preventive interventions.

Postmenopausal hormone therapy and the risk of rheumatoid arthritis: results from the Swedish EIRA population-based case-control study

To study the association between postmenopausal hormone therapy (PMH) use and the risk of rheumatoid arthritis (RA) stratifying the cases by the presence/absence of antibodies against citrullinated peptides (ACPA). A subset of the Epidemiological Investigation of RA (EIRA), a population-based case-control study, comprising postmenopausal women aged 50–70 living in Sweden, between 2006 and 2011 was analysed (523 cases and 1057 controls). All participants answered an extensive questionnaire, including questions regarding PMH use and potential confounders (education, smoking, BMI, oral contraceptives, reproductive factors). We calculated odds ratios (OR) of developing ACPA-positive/-negative RA, with 95 % confidence intervals (CI) and adjusted for age, residential area and smoking. Current users of PMH had a decreased risk of ACPA-positive RA compared with never users (OR 0.6, 95 % CI 0.3–0.9). The decreased risk was observed mainly in the age-group 50–59 years (OR 0.3, 95 % CI 0.1–0.8) but not in the age-group 60–70 years (OR 0.8, 95 % CI 0.4–1.4). Among current users of a combined therapy (estrogen plus progestogens) an OR of 0.3 (95 % CI 0.1–0.7) of ACPA-positive RA was observed, while no significant association was found among women who used estrogen only (OR 0.8, 95 % CI 0.5–1.6). No association between PMH use and ACPA-negative RA was found. PMH use might reduce the risk of ACPA-positive RA in post-menopausal women over 50 years of age, but not of ACPA-negative RA. The negative influence of this treatment on the risk of other chronic conditions cannot be overlooked.

Contraception and pregnancy counselling in rheumatoid arthritis

PURPOSE OF REVIEW

The purpose of this study is to encourage discussion of reproduction issues in all patients of fertile age in order to prevent unplanned and ill-timed pregnancies in patients with rheumatoid arthritis (RA).

RECENT FINDINGS

Counselling patients who desire children requires consideration of relevant reproductive health issues, including fertility, interaction of pregnancy and RA, and management during pregnancy and lactation. RA patients have no disease-related restrictions in regard to contraception, but need to be counselled on safe birth control particularly during treatment with potentially teratogenic drugs. In spite of mostly beneficial effects of pregnancy on RA, active disease and aggressive drug treatment can impair pregnancy outcomes. Options for drug therapy, though limited, may help to maintain low disease activity during pregnancy and lactation.

SUMMARY

Careful preconception counselling and risk assessment is important in RA women, with a particular focus on preventing unplanned pregnancy by information on contraception. Antibody status and all medications need to be reviewed before pregnancy. Maintaining low disease activity before and during pregnancy is crucial for good outcomes. Preconceptional counselling shared with all health professionals engaged in the care of a patient helps to ensure healthy pregnancy outcomes for mother and child.

Meta-analysis of oral contraceptives and rheumatoid arthritis risk in women

Background and objectives

Epidemiological investigations of the relationship between oral contraceptives and rheumatoid arthritis (RA) risk have reported controversial results. Therefore, a meta-analysis of case-control or cohort studies was performed to evaluate the role of oral contraceptives in relation to risk of developing RA.

Methods

Eligible studies were identified from databases PubMed and EMBASE by searching and reviewing references. Random effect models were utilized to summarize the relative risk (RR) estimates with 95% confidence intervals (CIs).

Results

A total of 12 case-control studies and five cohort studies were eligible for our analysis. No statistically significant association was observed between oral contraceptives and RA risk (RR=0.88, 95% CI=0.75–1.03). In the subgroup of geographic area, a decreased risk of borderline significance was observed for oral contraceptive users in European studies (RR=0.79, 95% CI=0.62–1.01), but this association did not emerge in the North American studies group (RR=0.99, 95% CI=0.81–1.21). No evidence for publication bias was detected (P for Egger’s test =0.231).

Conclusion

Our results of meta-analysis do not support the hypothesis of a protective effect of oral contraceptives on the risk for RA in women.

Association of environmental and genetic factors and gene-environment interactions with risk of developing rheumatoid arthritis

OBJECTIVE

We developed rheumatoid arthritis (RA) risk models based on validated environmental factors (E), genetic risk scores (GRS), and gene-environment interactions (GEI) to identify factors that can improve accuracy and reclassification.

METHODS

Models including E, GRS, and GEI were developed among 317 white seropositive RA cases and 551 controls from the Nurses' Health Studies (NHS) and validated in 987 white anti-citrullinated protein antibody-positive cases and 958 controls from the Swedish Epidemiologic Investigation of Rheumatoid Arthritis (EIRA), stratified by sex. Primary analyses included age, smoking, alcohol, parity, weighted GRS using 31 non-HLA alleles and 8 HLA-DRB1 alleles, and the HLA × smoking interaction. Expanded models included reproductive, geographic, and occupational factors and additional GEI terms. Hierarchical models were compared for discriminative accuracy using the area under the receiver operating characteristic curve (AUC) and reclassification using the integrated discrimination improvement (IDI) and the continuous net reclassification improvement.

RESULTS

The mean age at RA diagnosis was 56 years in the NHS and 51 years in the EIRA. Primary models produced AUCs of 0.716 in the NHS, 0.716 in women in the EIRA, and 0.756 in men in the EIRA. Expanded models produced improvements in discrimination with AUCs of 0.738 in the NHS, 0.724 in women in the EIRA, and 0.769 in men in the EIRA. Models including genetic factors (G) or G + GEI improved reclassification over E models; the full E + G + GEI model provided the optimal predictive ability by IDI analyses.

CONCLUSION

We have developed comprehensive RA risk models incorporating E, G, and GEI that have improved the discriminative accuracy for RA. Further work developing and assessing highly specific prediction models in prospective cohorts is still needed to inform primary RA prevention trials.

Dealing with clinical heterogeneity in meta-analysis. Assumptions, methods, interpretation

OBJECTIVE

There is an ongoing debate how to interpret findings of meta-analyses when substantial clinical heterogeneity is present among included trials. The aim of the present study was to demonstrate various ways of dealing with clinical heterogeneity along with underlying assumptions and interpretation. A recent meta-analysis on long-term psychodynamic psychotherapy (LTPP) was used as an illustrative example.

METHOD

Re-analysis of published data including calculation of a prediction interval, heterogeneity tests, Bayesian meta-analysis, meta-regression, and subgroup analysis to explore and interpret summary estimates in clinically heterogeneous studies.

RESULTS

Meta-analytic results and their implications varied considerably depending on whether and how clinical heterogeneity was addressed.

CONCLUSIONS

Whether or not to trust summary estimates in meta-analysis depends largely on the subjective relevance of clinical heterogeneity present. No single analysis and interpretation strategy can be valid in every context or paradigm, thus, reflection of own beliefs on the role of heterogeneity is needed.

Tobacco and other environmental risk factors in rheumatoid arthritis

Many environmental factors have been associated with an increased risk of developing Rheumatoid Arthritis (RA), but so far smoking is the only environmental risk factor that has been extensively studied and widely accepted. Smoking is associated with an increased risk of developing seropositive RA (RF and/or ACPA). Recent studies show that tobacco smoking can influence disease phenotype, with the development of more aggressive disease and greater joint damage; but other studies show contradictory results. Recent data suggests that response to antirheumatic therapy in RA is worse in smokers. In this article we review different environmental factors that have been associated with an increased risk of developing RA, with a special interest in tobacco smoking.

Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event

BACKGROUND

Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention.

METHODS

Using a collection of reviews identified previously, 166 references including a meta-analysis were selected for review. At least one of the primary outcomes in each review was an adverse or unintended event. The nature of the intervention, source of funding, number of individual meta-analyses performed, number of primary studies included in the review, and use of meta-analytic methods were all recorded. Specific areas of interest relating to the methods used included the choice of outcome metric, methods of dealing with sparse events, heterogeneity, publication bias and use of individual patient data.

RESULTS

The 166 included reviews were published between 1994 and 2006. Interventions included drugs and surgery among other interventions. Many of the references being reviewed included multiple meta-analyses with 44.6% (74/166) including more than ten. Randomised trials only were included in 42.2% of meta-analyses (70/166), observational studies only in 33.7% (56/166) and a mix of observational studies and trials in 15.7% (26/166). Sparse data, in the form of zero events in one or both arms where the outcome was a count of events, was found in 64 reviews of two-arm studies, of which 41 (64.1%) had zero events in both arms.

CONCLUSIONS

Meta-analyses of adverse events data are common and useful in terms of increasing the power to detect an association with an intervention, especially when the events are infrequent. However, with regard to existing meta-analyses, a wide variety of different methods have been employed, often with no evident rationale for using a particular approach. More specifically, the approach to dealing with zero events varies, and guidelines on this issue would be desirable.

Modifiable risk factors for RA: prevention, better than cure?

Objective. To perform a meta-synthesis of the evidence for modifiable lifestyle risk factors for inflammatory polyarthritis (IP) and RA.

Methods. We performed a MEDLINE literature search. Case–control and cohort studies and systematic reviews published from 1948 through February 2011 and studying modifiable risk factors for RA were retrieved. The main outcome measure was diagnosis of RA according to the standard criteria.

Results. Smoking contributes up to 25% of the population burden of RA. The risk is dose related, stronger in males and especially strong for anti-citrullinated peptide antibody positive (ACPA⁺) RA through an interaction with the shared epitope. After smoking cessation, there is, however, a latency of up to 20 years to return to baseline risk. Other associations are less definitive; however, prospective studies suggest that dietary antioxidants and breastfeeding may be protective and that high coffee consumption may increase RA risk. An inverse association with alcohol intake (especially in smokers) and with education/social class (especially seropositive RA) and an increased risk with obesity (seronegative RA) is also noted.

Conclusion. There is a need for further large-scale prospective studies with a consistent definition of RA phenotype (undifferentiated IP through to ACPA⁺/RF⁺ disease). This will ultimately afford the opportunity to evaluate preventative population strategies for RA akin to the well-established programmes for cardiovascular disease and cancer, targeting common risk factors.

Preclinical rheumatoid arthritis: identification, evaluation, and future directions for investigation

Rheumatoid arthritis (RA) likely develops in several phases, beginning with genetic risk, followed by asymptomatic autoimmunity, then finally, clinically apparent disease. Investigating the phases of disease that exist prior to the onset of symptoms (ie, the preclinical period of RA) will lead to understanding of the important relationships between genetic and environmental factors that may lead to disease, as well as allow for the development of predictive models for disease, and ultimately preventive strategies for RA.

Is the incidence of rheumatoid arthritis rising?: results from Olmsted County, Minnesota, 1955-2007

OBJECTIVE

To examine trends in the incidence and prevalence of rheumatoid arthritis (RA) from 1995 to 2007.

METHODS

To augment our preexisting inception cohort of patients with RA (1955-1994), we assembled a population-based incidence cohort of individuals >or=18 years of age who first fulfilled the American College of Rheumatology 1987 criteria for the classification of RA between January 1, 1995 and December 31, 2007 and a cohort of patients with prevalent RA on January 1, 2005. Incidence and prevalence rates were estimated and were age-and sex-adjusted to the white population in the US in 2000. Trends in incidence rates were examined using Poisson regression methods.

RESULTS

The 1995-2007 incidence cohort comprised 466 patients (mean age 55.6 years), 69% of whom were female and 66% of whom were rheumatoid factor positive. The overall age- and sex-adjusted annual RA incidence was 40.9/100,000 population. The age-adjusted incidence in women was 53.1/100,000 population (versus 27.7/100,000 population in men). During the period of time from 1995 to 2007, the incidence of RA increased moderately in women (P = 0.02) but not in men (P = 0.74). The increase was similar among all age groups. The overall age- and sex-adjusted prevalence on January 1, 2005 was 0.72% (95% confidence interval [95% CI] 0.66, 0.77), which is an increase when compared with a prevalence of 0.62% (95% CI 0.55, 0.69) in 1995 (P < 0.001). Applying the prevalence on January 1, 2005 to the US population in 2005 showed that an estimated 1.5 million US adults were affected by RA. This is an increase from the previously reported 1.3 million adults with RA in the US.

CONCLUSION

The incidence of RA in women appears to have increased during the period of time from 1995 to 2007. The reasons for this recent increase are unknown, but environmental factors may play a role. A corresponding increase in the prevalence of RA was also observed.

Graphical displays for meta-analysis: An overview with suggestions for practice

Meta-analyses are fundamental tools for collating and synthesizing large amounts of information, and graphical displays have become the principal tool for presenting the results of multiple studies of the same research question. We review standard and proposed graphical displays for presentation of meta-analytic data, and offer our recommendations on how they might be presented to provide the most useful and user-friendly illustrations. We concentrate on graphs that specifically aim to present similar sorts of univariate results from multiple studies. We start with forest plots and funnel plots, and proceed to Galbraith (or radial) plots, L'Abbé (and related) plots, further plots useful for investigating heterogeneity, plots useful for model diagnostics and plots for illustrating likelihoods and Bayesian meta-analyses. Copyright © 2010 John Wiley & Sons, Ltd.

Estrogens and the risk of complex regional pain syndrome (CRPS)

OBJECTIVE

Since complex regional pain syndrome (CRPS) shows a clear female predominance, we investigated the association between the cumulative as well as current exposure to estrogens, and CRPS.

METHODS

A population-based case-control study was conducted in the Integrated Primary Care Information (IPCI) project in the Netherlands. Cases were identified from electronic records (1996-2005) and included if they were confirmed during a visit (using International Association for the Study of Pain Criteria), or had been diagnosed by a specialist. Controls were matched to cases on gender, age, calendar time, and injury. Measures of cumulative endogenous estrogen exposure were obtained by questionnaire and included age of menarche and menopause, menstrual life, and cumulative months of pregnancy and breast-feeding. Current estrogen exposure at CRPS onset was retrieved from the electronic medical records and determined by current pregnancy or by the use of oral contraceptive (OC) drugs or hormonal replacement therapy (HRT).

RESULTS

Hundred and forty-three female cases (1493 controls) were included in analyses on drug use and pregnancies, while cumulative endogenous estrogen exposure was studied in 53 cases (58 controls) for whom questionnaire data were available. There was no association between CRPS and either cumulative endogenous estrogen exposure, OC, or HRT use. CRPS onset was increased during the first 6 months after pregnancy (OR: 5.6, 95%CI: 1.0-32.4), although based on small numbers.

DISCUSSION

We did not find an association between CRPS onset and cumulative endogenous estrogen exposure or current OC or HRT use, but more powered studies are needed to exclude potential minor associations.

Reproducibility of systematic literature reviews on food, nutrition, physical activity and endometrial cancer

Objective

Despite the increasing dependence on systematic reviews to summarise the literature and to issue public health recommendations, the formal assessment of the reliability of conclusions emerging from systematic reviews has received little attention. The main goal of the present study was to evaluate whether two independent centres, in two continents, draw similar conclusions regarding the association of food, nutrition and physical activity and endometrial cancer, when provided with the same general instructions and with similar resources.

Design

The assessment of reproducibility concentrated on four main areas: (1) paper search and selection; (2) assignment of study design; (3) inclusion of ‘key’ papers; and (4) individual studies selected for meta-analysis and the summary risk estimate obtained.

Results

In total 310 relevant papers were identified, 166 (54 %) were included by both centres. Of the remaining 144 papers, 72 (50 %) were retrieved in the searches of one centre and not the other (54 in centre A, 18 in centre B) and 72 were retrieved in both searches but regarded as relevant by only one of the centres (52 in centre A, 20 in centre B). Of papers included by both centres, 80 % were allocated the same study design. Agreement for inclusion of cohort-type and case–control studies was about 63 % compared with 50 % or less for ecological and case series studies. The agreement for inclusion of 138 ‘key’ papers was 87 %. Summary risk estimates from meta-analyses were similar.

Conclusions

Transparency of process and explicit detailed procedures are necessary parts of a systematic review and crucial for the reader to interpret its findings.

Strong combined gene-environment effects in anti-cyclic citrullinated peptide-positive rheumatoid arthritis: a nationwide case-control study in Denmark

OBJECTIVE

To study the role of shared epitope (SE) susceptibility genes, alone and in combination with tobacco smoking and other environmental risk factors, for risk of subtypes of rheumatoid arthritis (RA) defined by the presence or absence of serum antibodies against cyclic citrullinated peptides (CCPs).

METHODS

To address these issues, a nationwide case-control study was conducted in Denmark during 2002-2004, comprising incident cases of RA or patients with recently diagnosed RA (309 seropositive and 136 seronegative for IgG antibodies against CCP) and 533 sex- and age-matched population controls. Associations were evaluated by logistic regression analyses, in which odds ratios (ORs) served as measures of relative risk.

RESULTS

Compared with individuals without SE susceptibility genes, SE homozygotes had an elevated risk of anti-CCP-positive RA (OR 17.8, 95% confidence interval [95% CI] 10.8-29.4) but not anti-CCP-negative RA (OR 1.07, 95% CI 0.53-2.18). Strong combined gene-environment effects were observed, with markedly increased risks of anti-CCP-positive RA in SE homozygotes who were heavy smokers (OR 52.6, 95% CI 18.0-154), heavy coffee drinkers (OR 53.3, 95% CI 15.5-183), or oral contraceptive users (OR 44.6, 95% CI 15.2-131) compared with SE noncarriers who were not exposed to these environmental risk factors.

CONCLUSION

Persons who are homozygous for SE susceptibility genes, notably those who are also exposed to environmental risk factors, have a markedly and selectively increased risk of anti-CCP-positive RA. A distinction between anti-CCP-positive RA and anti-CCP-negative RA seems warranted, because these RA subtypes most likely represent etiologically distinct disease entities.

Therapy insight: guidelines for selection of contraception in women with rheumatic diseases

Use of contraceptives by women with rheumatic diseases, especially those with systemic lupus erythematosus, has long been thought to carry risks, such as disease exacerbation, thrombosis and other adverse effects. The use of effective contraception has, therefore, been avoided, despite many affected women being of reproductive age. Knowledge of risks and benefits of contraceptive methods in the general population has improved, as have the safety and effectiveness of hormonal contraceptives. Methods of administration have evolved and now include transdermal and intravaginal routes, a progesterone-releasing intrauterine device, and an extended-cycle oral contraceptive. Birth control pills are not all alike; the risk of adverse effects varies depending on the amount of estrogen and type of progestin used. Data show that patients with stable systemic lupus erythematosus are not at increased risk of disease flare while taking standard oral contraceptives. Despite a lack of randomized studies, evidence strongly suggests that the elevated risk of thrombosis makes estrogen-containing contraceptives unsuitable for patients with antiphospholipid antibody. Other important issues include potential interactions between hormonal contraceptives and other medications and possible risk of infection if an intrauterine device is used. Rheumatologists are increasingly working with gynecologists and patients to make choices about which contraceptive methods to use. Decisions should be individualized according to the patient's medical status, personal preference, and stage of reproductive life.

Tools for assessing quality and susceptibility to bias in observational studies in epidemiology: a systematic review and annotated bibliography

BACKGROUND

Assessing quality and susceptibility to bias is essential when interpreting primary research and conducting systematic reviews and meta-analyses. Tools for assessing quality in clinical trials are well-described but much less attention has been given to similar tools for observational epidemiological studies.

METHODS

Tools were identified from a search of three electronic databases, bibliographies and an Internet search using Google. Two reviewers extracted data using a pre-piloted extraction form and strict inclusion criteria. Tool content was evaluated for domains potentially related to bias and was informed by the STROBE guidelines for reporting observational epidemiological studies.

RESULTS

A total of 86 tools were reviewed, comprising 41 simple checklists, 12 checklists with additional summary judgements and 33 scales. The number of items ranged from 3 to 36 (mean 13.7). One-third of tools were designed for single use in a specific review and one-third for critical appraisal. Half of the tools provided development details, although most were proposed for future use in other contexts. Most tools included items for selection methods (92%), measurement of study variables (86%), design-specific sources of bias (86%), control of confounding (78%) and use of statistics (78%); only 4% addressed conflict of interest. The distribution and weighting of domains across tools was variable and inconsistent.

CONCLUSION

A number of useful assessment tools have been identified by this report. Tools should be rigorously developed, evidence-based, valid, reliable and easy to use. There is a need to agree on critical elements for assessing susceptibility to bias in observational epidemiology and to develop appropriate evaluation tools.

Environmental risk factors differ between rheumatoid arthritis with and without auto-antibodies against cyclic citrullinated peptides

The aim of this study was to evaluate new and previously hypothesised non-genetic risk factors for serologic subtypes of rheumatoid arthritis (RA) defined by the presence or absence of auto-antibodies to cyclic citrullinated peptides (CCP). In a national case-control study, we included 515 patients recently diagnosed with RA according to the American College of Rheumatology 1987 classification criteria and 769 gender- and age-matched population controls. Telephone interviews provided information about non-genetic exposures, and serum samples for patients were tested for anti-CCP-antibodies. Associations between exposure variables and risk of anti-CCP-positive and anti-CCP-negative RA were evaluated using logistic regression. A series of RA subtype-specific risk factors were identified. Tobacco smoking (odds ratio [OR] = 1.65; 95% confidence interval: 1.03–2.64, for >20 versus 0 pack-years) was selectively associated with risk of anti-CCP-positive RA, whereas alcohol consumption exhibited an inverse dose-response association with this RA subtype (OR = 1.98, 1.22–3.19, for 0 versus >0–5 drinks per week). Furthermore, coffee consumption (OR = 2.18; 1.07–4.42, for >10 versus 0 cups per day), ever use of oral contraceptives (OR = 1.65; 1.06–2.57) and having a first-degree relative with schizophrenia (OR = 4.18; 1.54–11.3) appeared more strongly associated with risk of anti-CCP-positive RA. Obesity was selectively associated with risk of anti-CCP-negative RA, with obese individuals being at more than 3-fold increased risk of this subtype compared with normal-weight individuals (OR = 3.45; 1.73–6.87). Age at menarche was the only examined factor that was significantly associated with both serologic subtypes of RA (p-trends = 0.01); women with menarche at age ≥ 15 years had about twice the risk of either RA subtype compared with women with menarche at age ≤ 12 years. Major differences in risk factor profiles suggest distinct etiologies for anti-CCP-positive and anti-CCP-negative RA.

Rheumatoid factor seropositivity is inversely associated with oral contraceptive use in women without rheumatoid arthritis

OBJECTIVES

To examine whether oral contraceptive use is associated with the presence of serum rheumatoid factor in women of reproductive age without rheumatoid arthritis.

METHODS

304 women selected from parents of children who were at increased risk of developing type 1 diabetes were studied, because they were enriched with the human leucocyte antigen-DR4 allele, a susceptibility marker for both type 1 diabetes and rheumatoid arthritis. Participants visited a clinic where blood was drawn for rheumatoid factor testing, and exposure data were collected via questionnaires. A medical history and joint examination were performed to rule out rheumatoid arthritis. Participants and examiners were unaware of the participants' rheumatoid factor status at the time of examination and questionnaire.

RESULTS

Use of oral contraceptives at any time was inversely associated with rheumatoid factor positivity (adjusted odds ratio (OR) 0.2, 95% confidence interval (CI) 0.07 to 0.52) independent of age, education and smoking. Smoking > or = 20 pack-years was also associated with rheumatoid factor positivity (adjusted OR 56.38, 95% CI 4.31 to 736.98) compared with never smoking. Smoking 1-19 pack-years was not associated with a positive rheumatoid factor.

CONCLUSIONS

Our results suggest that oral contraceptive use, and possibly cigarette smoking, act early in the development of the immune dysregulation that occurs in rheumatoid arthritis.

Prospective studies of dairy product and calcium intakes and prostate cancer risk: a meta-analysis

BACKGROUND

The Dietary Guidelines for Americans 2005 recommends that Americans increase their intake of dairy products. However, some studies have reported that increasing dairy product intake is associated with an increased risk of prostate cancer. We conducted a meta-analysis to examine associations between intakes of calcium and dairy products and the risk of prostate cancer.

METHODS

We searched Medline for prospective studies published in English-language journals from 1966 through May 2005. We identified 12 publications that used total, advanced, or fatal prostate cancer as end points and reported associations as relative risks (RRs) with 95% confidence intervals (CIs) by category of dairy product or calcium intake. Data were extracted using standardized data forms. Random-effects models were used to pool study results and to assess dose-response relationships between dairy product or calcium intakes and the risk of prostate cancer. We conducted sensitivity analyses by changing criteria for inclusion of studies or by using fixed-effects models. All statistical tests were two-sided.

RESULTS

Men with the highest intake of dairy products (RR =1.11 [95% CI = 1.00 to 1.22], P = .047) and calcium (RR = 1.39 [95% CI = 1.09 to 1.77], P = .018) were more likely to develop prostate cancer than men with the lowest intake. Dose-response analyses suggested that dairy product and calcium intakes were each positively associated with the risk of prostate cancer (Ptrend = .029 and .014, respectively). Sensitivity analyses generally supported these associations, although the statistical significance was attenuated. The pooled relative risks of advanced prostate cancer were 1.33 (95% CI = 1.00 to 1.78; P = .055) for the highest versus lowest intake categories of dairy products and 1.46 (95% CI = 0.65 to 3.25; P > .2) for the highest versus lowest intake categories of calcium.

CONCLUSIONS

High intake of dairy products and calcium may be associated with an increased risk of prostate cancer, although the increase appears to be small.

Safety concerns and health benefits associated with oral contraception

Since the introduction of hormonal contraceptives in the 1960s, there have been a variety of both health benefits and safety concerns attributed to their use. In most instances, the noncontraceptive benefits of oral contraceptives (OCs) outweigh the potential cardiovascular risks. In fact, the probability of a patient experiencing a cardiovascular event while taking a low-dose OC is very low. However, smoking, hypertension, obesity, and diabetes are risk factors that must be taken into account when prescribing OCs. The neoplastic effects of hormonal contraceptives have been extensively studied, and recent meta-analyses indicate that there is a reduction in the risk of endometrial and ovarian cancer, a possible small increase in the risk for breast and cervical cancer, and an increased risk of liver cancer. Finally, many women will experience noncontraceptive health benefits with OCs that expand far beyond pregnancy prevention. Some of these benefits include reduction in menstrual-related symptoms, fewer ectopic pregnancies, a possible increase in bone density, and possible protection against pelvic inflammatory disease.

Risks and benefits of oral contraceptive pills

In the more than 40 years since the combined oral contraceptive pill was first marketed, much information has been obtained as to its risks. Considerably less publicity has been given to the balancing benefits that have also emerged. There has been an increasing realization that the risks are focused in those women with recognised risk factors, meaning that the remainder can use the product with increasing reassurance. The doses of both hormones have also been lowered considerably since the early years. Thus, it can be a rational decision by a fully informed woman to use this form of contraception.

Health benefits of oral contraceptives

A sizeable literature corroborates the multiple health benefits of oral contraceptive use. The first estrogen/progestin combination pills were marketed to treat a variety of menstrual disorders. Although currently used oral contraceptives no longer carry FDA-approved labeling for these indications, they remain important therapeutic options for a variety of gynecologic conditions. Well-established gynecologic benefits include a reduction in dysmenorrhea and menorrhagia, iron-deficiency anemia, ectopic pregnancy, and PID. Although older, higher-dose pills reduced the incidence of ovarian cysts, low-dose pills suppress follicular activity less consistently. Nevertheless, cycle-related symptoms, including functional cysts, dysmenorrhea, chronic pelvic pain, and ovulation pain (mittelschmerz), generally improve. Women with polycystic ovary syndrome note improvement in bleeding patterns and a reduction in acne and hirsutism. Symptoms from endometriosis also improve with oral contraceptive therapy. Current data suggest that oral contraceptive therapy increases bone density and that past use decreases fracture risk. Oral contraceptives also improve acne, a major health concern of young women. Oral contraceptives provide lasting reduction in the risk of two serious gynecologic malignancies--ovarian and endometrial cancer. The data with respect to ovarian cancer are compelling enough to recommend the use of oral contraceptives to women at high risk by virtue of family history, positive carrier status of the BRCA mutations, or nulliparity, even if contraception is not required. Health care providers must counsel women regarding these benefits to counteract deeply held public attitudes and misconceptions regarding oral contraceptive use. Messages should focus on topics of interest to particular groups of women. The fact that oral contraceptives increase bone mineral density and reduce ovarian cancer is of great interest to women in their forties and helps influence use and compliance in this group. In contrast, the beneficial effects of oral contraceptives on acne resonates with younger women. Getting the good news out about the benefits of oral contraceptives will enable more women to take advantage of their positive health effects.

Menopause, oestrogens and arthritis

The menopause coincides with the appearance of many of the common arthritic conditions and with the lessening of severity of others such as SLE. The hormonal changes that occur may modulate these diseases. Thus, hormonal manipulation may have either beneficial or detrimental effects on the incidence and activity of a number of common joint diseases. We review the evidence regarding the effect of the menopause and oestrogen replacement therapy on the pathogenesis, incidence and prevalence and disease activity of osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus and carpal tunnel syndrome.

Characteristics of a population of women with breast implants compared with women seeking other types of plastic surgery

Several previous studies have shown that breast implant patients demonstrate a number of differences compared with the general population. However, studies have not compared patients with breast implants with women receiving other types of plastic surgery, of interest because this latter group has been proposed as a comparison group for assessing the long-term health effects experienced by breast implant patients. Questionnaire data obtained from 7447 breast implant patients and 2203 patients with other types plastic surgery were collected during the course of a retrospective cohort study, to determine whether implant patients demonstrate different characteristics compared with a more restricted group of patients. In contrast to previous investigations that compared implant patients with the general population, distinctive differences with respect to family income, number of pregnancies, alcohol consumption, cigarette smoking, or histories of previous gynecologic operations or operations for benign breast disease were not found. However, implant patients were significantly more likely than other plastic surgery patients to be white, have low levels of education, have early ages at first birth, be thin, and be screened frequently for breast disease. Furthermore, implant patients reported somewhat greater use of exogenous hormones and familial histories of rheumatoid arthritis. These results support the notion that other plastic surgery patients are a more appropriate comparison group than women in the general population for studies of the health effects of breast implants; however, there continue to be distinctive characteristics possessed by breast implant patients, which need to be taken into account in an assessment of what disease effects can be uniquely attributed to silicone breast implants.

Modulating the Th1/Th2 balance in inflammatory arthritis

The balance between Th1 and Th2 cells regulates the choice between inflammatory and antibody-mediated immune responses. To an increasing extent this balance is thought to involve the participation of antigen-presenting cells, rather than the entirely autonomous activity of T cells and their cytokines. Here we survey current opinion concerning the working of this balance, and its condition in rheumatoid arthritis and the other inflammatory arthritides. The contrast between Lyme arthritis and reactive arthritis is particularly illuminating, since one is triggered by extracellular and the other by intracellular infection. We describe current approaches to the modulation of this balance. Guided by the principles that genetic polymorphism is likely to identify relevant genes, that any cytokine gene picked up by a virus must matter and that natural immunosuppressive activity at mucosal surfaces should be worth exploiting, we identify as particularly worthy of attention: (i) IL-10, (ii) inhibitors of IL-12 production, (iii) inhibitors of CD40 ligand expression and (iv) oral and nasal tolerance. Other protective T cell subsets are touched on, and the impact of oligonucleotide arrays mentioned.

Serum androgen-anabolic hormones and the risk of rheumatoid arthritis

OBJECTIVE

It has been hypothesised, mainly on the basis of indirect evidence, that low serum concentrations of androgen-anabolic hormones would play a causal part in the aetiology of rheumatoid arthritis (RA).

METHODS

A case-control study was nested with a Finnish cohort of 19,072 adults who had neither arthritis nor a history of it at the baseline examination during 1973-1977. Pre-illness serum specimens for the assay of testosterone and dehydroepiandrosterone sulphate (DHEAS) were available from 116 cases who had developed RA by late 1989. Three controls per each incident case were individually matched for sex, age, and municipality.

RESULTS

The mean testosterone concentration was 1.4 nmol/l in those 84 women who developed RA and 1.4 nmol/l in their controls; the corresponding figures for DHEAS were 5.2 mumol/l and 5.5 mumol/l, respectively. Mean testosterone concentration in the 32 male cases was 26.1 nmol/l and 26.4 nmol/l in their controls; the corresponding figures for DHEAS were 11.2 mumol/l and 10.1 mumol/l, respectively. Analysis by subgroups (rheumatoid factor positive and negative disease, pre-menopausal and postmenopausal women) and by hormone distributions showed no differences.

CONCLUSION

The findings are not in line with the contention that low concentrations of testosterone and DHEAS play a part in the aetiology of RA.

Oral contraceptives and rheumatoid arthritis: results from a primary care-based incident case-control study

OBJECTIVE

The possibility that oral contraceptives offer a protective effect against the development of rheumatoid arthritis is still contentious. Of the 17 studies investigating this association, 11 have found a protective effect, and 6 have not. These differences are probably attributable to either selection or information biases in a subset of studies, although the exact reason is unknown. To overcome the methodological problems inherent in the design of previous studies, we have conducted a population-based case-control study.

METHODS

Women who were incident cases of inflammatory polyarthritis, defined as swelling of at least two joint areas lasting at least 4 weeks, were recruited directly from primary care and compared with age-matched women from the same population.

RESULTS

Cases and controls reported a similar level of "ever use" of oral contraceptives, adjusted odds ratio = 0.88 (95% confidence interval, 0.47, 1.64). The cases were, however, less likely to report using oral contraceptives at the time of onset, adjusted odds ratio = 0.22 (95% confidence interval, 0.06, 0.85). Similar results were observed for cases who satisfied the criteria for rheumatoid arthritis and cases who did not.

CONCLUSION

These results indicate that only current oral contraceptive use protects against the development of inflammatory polyarthritis.