Is pregnancy a risk factor in the causation of rheumatoid arthritis?

Family history of autoimmune diseases is associated with an increased risk of autism in children: A systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis to summarize the current evidence on the relationship between family history of autoimmune diseases (ADs) and risk of autism in children, as current evidence suggests inconsistent results.

METHODS

We identified relevant studies by searching PubMed, EmBase, and Web of Science databases up to Dec 2014. Risk estimates from individual studies were pooled using random-effects models. Sub-groups analyses were conducted by some study-level factors. Publication bias was assessed by funnel plots, Egger's regression test and Begg-Mazumdar test.

RESULTS

A total of 11 articles were included in the meta-analysis, including 3 cohort studies, 6 case-control studies, and 2 cross-sectional studies. The meta-analysis showed that family history of all ADs combined was associated with a 28% (95% CI: 12-48%) higher risk of autism in children. For some specific ADs, evidence synthesis for risk of autism in children showed a statistically significant association with family history of hypothyroidism (OR=1.64, 95% CI: 1.07-2.50), type 1 diabetes (OR=1.49, 95% CI: 1.23-1.81), rheumatoid arthritis (OR=1.51, 95% CI: 1.19-1.91), and psoriasis (OR=1.59, 95% CI: 1.28-1.97). The results varied in some subgroups.

CONCLUSION

An overall increased risk of autism in children with family history of ADs was identified. More mechanistic studies are needed to further explain the association between family history of ADs and increased risk of autism in children.

Parity, time since last live birth and long-term functional outcome: a study of women participating in the Norfolk Arthritis Register

OBJECTIVE

To investigate the relationship between pre-symptom onset live births and functional outcome in women with inflammatory polyarthritis (IP).

METHODS

1872 women with no subsequent pregnancies were registered with the Norfolk Arthritis Register between 1990 and 2004 and followed-up for a median of 5 years. Functional disability over time was assessed by Health Assessment Questionnaire (HAQ). The number and calendar year of past live births were recorded. Differences in HAQ score over time by parity and time since last live birth (latency), adjusted for age and symptom duration, were examined using linear random effects models. The results were then adjusted for a number of potential confounders.

RESULTS

1553 women (83%) had ≥1 live births before symptom onset. The median latency was 26 years (IQR 16-35). Parous women had significantly lower HAQ scores over time than nulliparous women (-0.19, 95% CI -0.32 to -0.06). Increasing latency was associated with increasing HAQ score; the mean HAQ score of women with a latency of approximately 32 years was the same as for nulliparous women. This was independent of autoantibody status, socioeconomic status, smoking history and comorbidity.

CONCLUSION

Parous women who develop IP have better functional outcome over time than nulliparous women who develop IP. The beneficial effect of parity diminishes with time.

The association between gravidity and primary biliary cirrhosis

PURPOSE

Primary biliary cirrhosis is an autoimmune disease with female predominance that leads to liver failure. The goal of this study was to identify reproductive risk factors associated with this disease.

METHODS

We compared 182 cases of PBC with 225 age- and sex-matched friend controls to examine the role of reproductive factors. The survey instrument was developed using standardized questions obtained from the National Health and Nutrition Examination Survey (NHANES) III.

RESULTS

A total of 126/182 cases (69%) and 141/225 (62.6%) friend controls responded to the survey. More cases than controls reported ever having genitourinary infection [adjusted odds ratio (OR) = 2.12, 95% confidence interval (CI) 1.01, 4.42] among those without a personal or family history of autoimmune disease. The most notable finding was that cases reported significantly more pregnancies than controls (p = 0.008). The adjusted OR for each additional pregnancy among those without a personal or family history of autoimmune disease was 1.40 (95% CI 1.14, 1.7). More controls (24.4%) than cases (16.0%) were nulliparous. Cases reported having five or more children (16.0%) with double the frequency of controls (8.2%).

CONCLUSIONS

The association reported herein, between primary biliary cirrhosis and gravidity, is particularly significant because of the overwhelming female predominance.

The lack of associations between rheumatoid arthritis and both nulliparity and infertility

OBJECTIVES

Rheumatoid arthritis (RA) is an autoimmune disease that occurs more commonly in women and frequently onsets in women of childbearing age. Pregnancy often causes disease remission, with a subsequent flare postpartum. Nulliparity may be a risk factor for RA, but the literature does not consistently report this finding. There may be a production of antibodies in women with RA that could lead to infertility, and subsequent nulliparity, but this has not been proved. We wanted to determine whether there was a relationship between nulliparity, infertility, oral contraceptive use, and adverse pregnancy outcome in women with newly diagnosed RA.

METHODS

Through a case control study, using a mailed questionnaire, we compared the fertility and pregnancy outcome histories of 34 women between the ages of 19 and 44 years with recent-onset RA with 68 healthy controls matched for age and marital status. The response rate was 97%. A review of the literature also was performed to study the associations between RA and infertility and nulliparity, using Medline searching key references.

RESULTS

We found no association between infertility and the onset of RA. Seventy-one percent of women with RA and 68% of controls had been pregnant. There was a trend toward increased nulliparity in these patients, but the result was not statistically significant (odds ratio [OR], 1.4; P<.6). There were no differences in the number of children (2.6 v. 2.7; P<.6) and parity outcomes in the two groups. Age at first pregnancy was younger in the women with RA (22.6 v. 25.5 years; P<.008), but the education level was higher in the controls (P<.0001), which may explain these differences. Oral contraceptive use was lower in the RA women, but more RA women had long-term use (greater than or equal to 5 years), and neither result was statistically significant. Literature review shows that at best, there are weak negative associations between current estrogen use and RA, and no association with nulliparity and infertility.

CONCLUSIONS

It appears that infertility, the number of pregnancies, and pregnancy outcome are not strongly associated with the risk of developing RA in women of childbearing age. However, in this study there may have been selection biases in the women with RA and the controls that differentially could have affected their reproductive outcomes. Thus, a true association could have been missed. Most other published studies find no association between nulliparity and RA.

Influence of HLA-class II incompatibility between mother and fetus on the development and course of rheumatoid arthritis of the mother

OBJECTIVE

To assess the relation between the course of rheumatoid arthritis (RA) during pregnancy or the onset of RA postpartum and DRB1, DQA1, and DQB1 incompatibilities between mother and child.

METHODS

In 45 pregnancies of 33 RA patients the course of RA was related to the number of class II incompatibilities. Furthermore class II incompatibilities in 16 pregnancies followed by RA onset were compared with those in 87 control pregnancies.

RESULTS

The risk of a favourable compared with an unfavourable course was 0.95, 2.67, and 2.38 in case of DRB1, DQA1, and DQB1 incompatibility respectively. DQA1 and DQB1 incompatibilities were seen more often in the 10 pregnancies followed by RA onset within three months than in control pregnancies (OR 8.02, 95% CI 0.97, 66.06 and OR 8.79 95% CI 1.07, 72.46 respectively).

CONCLUSIONS

DQA1 and DQB1 incompatibility between mother and child seems to have a favourable effect on the course of RA and may postpone the risk of RA onset during pregnancy.

Epidemiological and clinical aspects relating to the variability of rheumatoid arthritis

OBJECTIVE

To review epidemiological studies dealing with the temporal and geographic variability in the occurrence of rheumatoid arthritis (RA) and clinical studies that address the variability of severity and manifestations among populations.

METHODS

An extensive search of the literature, including a Medline search, was completed. Studies addressing the origin, history, and trends in the occurrence of RA were reviewed first. Next, studies of the prevalence and incidence of RA in different populations were reviewed, and occurrence rates compared. Standardization was attempted by tabulating adult prevalence rates of studies using equivalent sets of criteria. Studies comparing RA patients from two populations were sought next. Finally, studies dealing with explanations of the presumed variability were reviewed.

RESULTS

Temporal variability is indicated by paleopathological evidence that RA has existed in the New World since 4000 BC, whereas there is no evidence that it occurred in Europe before the 17th century, or in Africa before the 20th century. Epidemiological studies show a possible trend of decreasing incidence of RA in the United States and Western Europe, whereas reports from Africa note a rising incidence. In white populations of Europe and America, prevalence is approximately 1%, and incidence is 0.03%. Significantly higher rates are found in some North American Indians, and significantly lower rates in some Asian and African populations, even when the different population structures are taken into account. In the latter populations, different patterns of occurrence from those observed in whites emerge, such as greater female preponderance and a much younger peak age at onset. Direct standardized comparisons of two diverse populations of RA patients showed some differences in expression, severity, or manifestations of RA between populations.

CONCLUSION

The occurrence and manifestations of RA are temporally and geographically variable.

Oral contraception, parity, breast feeding, and severity of rheumatoid arthritis

OBJECTIVE

To investigate the influence of breast feeding, use of the oral contraceptive pill (OCP), and parity on rheumatoid arthritis (RA).

METHODS

One hundred and seventy six women with RA were compared with 145 control subjects; all had at least one child. RA patients were classified as having severe (n = 82) or mild disease (n = 89) according to clinical joint evaluation, radiological score, biological inflammation, and the presence of HLA-DR1 or -DR4 alleles.

RESULTS

The mean age of RA patients was 58 years, and the mean age at the time of diagnosis of RA was 46 years. The mean time between onset of RA and the first birth was 23.6 (SD 3.8) years. The OCP user rates were 33% in the RA group and 47.6% in the control group (p < 0.02). OCP use was related to the mother's year of birth. The relative risk for developing RA was 0.598 (95% confidence interval (CI) 0.33 to 1.1) in women who had used OCP for more than five years compared with those who had never used OCPs. In contrast, the age at which the first pregnancy occurred, the number of children breast fed, and the duration of breast feeding were comparable in RA patients and healthy subjects. Among the RA patients, parity, duration of breast feeding, and the number of breast fed children were significantly increased in those with severe disease. Having more than three children increased the risk of developing severe disease 4.8-fold when adjusted for age and OCP use. Forty six percent of women with severe RA had a history of breast feeding duration greater than six months before disease onset, compared with 26% of patients with mild disease (p < 0.008). Having more than three breast fed children increased the risk of poor disease prognosis 3.7-fold. In contrast, OCP use had a protective role in the course of RA (44% of RA patients with mild disease were OCP users, compared with 21.7% of those with severe RA; p < 0.001). Among those using OCP for more than five years, the relative risk of developing severe disease was 0.1 (95% CI 0.01 to 0.6), after adjustment for age, parity, and breast feeding.

CONCLUSION

Our results suggest that parity, and to a lesser extent breast feeding, before RA onset worsened RA prognosis, whereas OCP use had a protective role. Prolactin and oestrogen may have a role in these effects.

Hormonal and pregnancy relationships to rheumatoid arthritis: convergent effects with immunologic and microvascular systems

OBJECTIVE

To review sex hormones and rheumatoid arthritis (RA) and the interrelationships between hormonal, immunological, and vascular systems.

DATA SOURCES

Publications detailing serum sex hormone levels and their HLA interactions, steroidogenesis, pregnancy, and therapeutic uses of sex hormones in RA.

STUDY SELECTION

Controlled studies of sex hormone levels in RA patients not previously treated with glucocorticoids.

DATA EXTRACTION

Mean (+/- SD) serum levels of dehydroepiandrosterone sulfate (DHEAS), testosterone (T), and estradiol (E2).

DATA SYNTHESIS

Mean (+/- SD) levels were collated into tables for women with pre-versus postmenopausal onsets of disease and men. Data were also ordered across all study groups by increasing mean levels of the control subjects. Pooled data were summarized statistically, and major sources of variation between the studies were identified.

CONCLUSIONS

Serum DHEAS, an adrenal androgen, was impressively decreased among women with premenopausal onset of RA. One study showed such deficiency years before disease onset. Serum T was somewhat decreased in the premenopausal onset group, but could be explained by decreased peripheral conversion of the lower levels of adrenal androgens. Women with postmenopausal onset of RA had modestly decreased serum DHEAS levels overall, but no difference in serum T, compared with controls. Male RA cases had consistently decreased serum levels of T, but not of DHEAS. Serum E2 was comparable in all RA versus control groups. The complex biology of pregnancy was interpreted as an example of vital interactions between hormonal, immunological, and vascular systems, as they may relate to the physiopathology of RA. The major age, sex, and hereditable determinants of RA were compared within a composite table of estimated relative risks. Elucidation of the interacting risk factors offers promising avenues of research in this complex disease.

Timing of pregnancy in relation to the onset of rheumatoid arthritis

The interval between the onset of rheumatoid arthritis (RA) and the most recent pregnancy prior to RA onset in 88 women was determined. These data were compared with data obtained from a group of 144 age-matched normal women (controls) who had been assigned a "dummy date for RA onset" for the purposes of analysis. The frequency of disease onset during 3 time intervals within the period from conception to 1 year postpartum was compared with the frequency of disease onset outside this period. There was a reduction in the incidence of disease onset during pregnancy (adjusted odds ratio [OR] 0.30, 95% confidence interval [CI] 0.04-2.6) and a numerically greater increased risk of RA onset during the first 3 months postpartum (OR 5.6, 95% CI 1.8-17.6), which persisted for the subsequent 9 months (OR 2.6, 95% CI 0.8-7.9). A reduction in the incidence of disease onset was seen during all pregnancies; in contrast, the postpartum increase was greater in those with RA onset after the first pregnancy. The reduced incidence of RA onset during pregnancy, with the increased risk postpartum, mirrors the previously described suppression of disease activity during pregnancy and the subsequent flare postpartum in women with established RA. In addition, the increased postpartum risk after the first pregnancy might suggest that in susceptible women, either the hormonal changes or the exposure to the fetus's paternal HLA might represent a risk factor for disease causation.

Pregnancy and the risk of developing rheumatoid arthritis

There have been conflicting reports on, and no plausible biologic explanation for, a protective effect of oral contraceptive (OC) use on the development of rheumatoid arthritis (RA). Therefore, we investigated aspects of behavior related to OC use that could explain the preventive effect of OC on the onset of RA. In the present case-control study, past pregnancy, age at first pregnancy, and pregnancies with adverse outcome were studied as possible risk factors for RA. Interview information on reproductive variables was obtained from 135 young adult women with confirmed definite or classic RA of recent onset, and from 378 control patients with soft tissue rheumatic disorders or osteoarthritis. All patients had at least 2 years of followup to confirm the consistency of the diagnosis. We found a decreased risk of RA in women who had been pregnant. The risk of RA in women who had ever been pregnant compared with women who had never been pregnant was 0.49 (95% confidence interval 0.27-0.91). The earlier the first pregnancy, the lower the risk of RA. Pregnancy with adverse outcome (i.e., gestation less than 25 weeks) did not substantially change the risk of RA (relative risk 0.73, 95% confidence interval 0.50-1.07). The protective effect of pregnancy was independent of OC use, the presence of HLA-DR4, or a family history of RA. Immune modulation by female hormonal influences could be an explanation for the results of the present study.

Oral contraceptives and rheumatoid arthritis: new data from the Royal College of General Practitioners' oral contraception study

From data available at April 1987 it was found that the standardised risk ratio for rheumatoid arthritis between current users of oral contraceptives and never users was 0.82 (95% confidence interval 0.59 to 1.15); the ratio between former users and never users was 0.94 (95% confidence interval 0.72 to 1.22). Important secular trends have occurred within our study population. The incidence of rheumatoid arthritis among former and never users has declined over the past two decades. Current users have not experienced this temporal trend, and the ratio between current and never users has, therefore, approached unity. These secular changes may explain why some studies have found that oral contraceptives have a protective effect, while others have been unable to show such an effect.

Pregnancy and rheumatoid disease

The onset of pregnancy appears to result in the amelioration of rheumatoid disease activity. This is most likely to be related to the change in hormonal, and thus immunological, status of the mother. Spontaneous abortion appears to be increased in mothers with rheumatoid disease. Whether this is due to disease status or to drug therapy is not entirely clear for all cases, but there is a suggestion that it could be the disease state. If at all possible, drugs should be avoided during pregnancy but simple anti-inflammatory drugs in low dosage probably do not produce any major problems. Immunosuppressant drugs should be avoided at all times except when the mother's health is at serious risk. The continued use of disease remitting agents throughout pregnancy is probably not necessary and there is still sufficient question as to whether these drugs could be potentially toxic to the infant. Primum non nocere.

The influence of pregnancy and reproductive span on the occurrence of autoimmune thyroiditis

A study comparing the reproductive histories of 89 women affected by Hashimoto's thyroiditis (HT) with 89 matched controls has been carried out to determine whether endogenous hormones contribute to the development of the disease. There was no evidence of an association between HT and parity and no trend to an increasing disease risk with increasing parity. However, patients with HT had a longer reproductive span. There was a significant trend to a lower risk with later age at menarche (relative risk (RR) of menarche at 13-14 years compared with less than or equal to 12 years = 0.71, and greater than or equal to 15 years compared with less than or equal to 12 years = 0.45), and an increased risk with a later menopause (greater than or equal to 51 years compared with less than or equal to 50 years, RR = 3.00, P less than 0.025). An additional finding was an increased hysterectomy rate among the cases. These observations may be explained if the hyperoestrogenic state associated with a longer reproductive span acted to modulate the immune process in autoimmune thyroid disease.

Reduction of the risk of rheumatoid arthritis among women who take oral contraceptives

Discrepant results among investigations of the association between oral contraceptive use and rheumatoid arthritis (RA) have been ascribed to shortcomings in the study methods. In the present study, we obtained detailed information on oral contraceptive use in 135 young women with confirmed definite or classic RA of recent onset and in 378 controls with soft tissue rheumatism or osteoarthritis. All patients had at least 2 years of followup to confirm the consistency of the diagnosis. Oral contraceptive use at any time before disease onset was reported by 70% of the RA patients and 85% of the controls; the latter figure corresponded to general population data for The Netherlands. This yielded a relative risk for RA of 0.39 among those who had ever used oral contraceptives and 0.58 for those using oral contraceptives at the time of symptom onset. The preventive effect of oral contraceptive use on the risk of RA was found to be independent of the dose, duration of use, or presence of HLA-DR4. The strongest protection was seen in women with a family history of RA and in women ages 31-40 at symptom onset. The conflicting results in the literature are discussed, and a possible biologic mechanism for this phenomenon is suggested.

Is poor pregnancy outcome a risk factor in rheumatoid arthritis?

Previous work has suggested that prior poor reproductive outcome may be a risk factor in rheumatoid arthritis (RA). A case-control study of 195 women with RA and 462 control women from two different sources is presented here. No increase in rates of spontaneous abortion was seen in the women with RA; indeed a protective effect was seen with an age adjusted odds ratio of 0.6 (95% confidence interval (CI) 0.4 to 0.9). A non-significant increase in stillbirth rates was seen in women with RA, producing an age adjusted odds ratio of 1.5 (95% CI 0.7 to 3.4). No differences in rates of induced abortion were seen. Thus although hormonal and gynaecological factors are undoubtedly important in the aetiology of RA, it was not possible to confirm that prior poor reproductive outcome is a risk factor in RA.

Adverse reproductive outcomes in women who subsequently develop rheumatoid arthritis

The rates of adverse reproductive outcomes in 40 women with rheumatoid arthritis (RA) were compared with 67 of their unaffected female relatives. All women were aged between 35 and 65 years at the time of inquiry. Seven of the women with RA reported a perinatal death (six stillbirths, one early neonatal death) compared with one women in the unaffected group: estimated age adjusted relative risk (R) = 12.4, 95% confidence interval (95% CI) 1.6-91.1. The rate of spontaneous abortions was, however, not significantly different between the two groups (R = 1.2, 95% CI 0.5-2.9). All the perinatal deaths occurred before clinical disease onset in the women with RA. It is possible that in these two groups of women with a similar genetic background perinatal loss may be related, at least in part, to disease expression.

Alterations in carbohydrate composition of serum IgG from patients with rheumatoid arthritis and from pregnant women

The carbohydrate composition of IgG purified from serum of patients with rheumatoid arthritis (RA), pregnant women, and blood donors has been determined by gas-liquid chromatography. Comparison of the results indicates that IgG from patients with RA contains significantly less galactose but more N-acetylglucosamine than normal IgG, whereas the fucose and sialic acid contents are not changed. The carbohydrate content of IgG in RA is reduced. IgG in pregnancy contains more galactose and more sialic acid than normal IgG, whereas fucose, N-acetylglucosamine, and the total carbohydrate content are not changed. These data suggest a temporal compensation of the RA associated undergalactosylation of IgG in female patients with RA during pregnancy, a period during which remission of the disease is often observed.