The protective effect of the oral contraceptive pill on rheumatoid arthritis: an overview of the analytic epidemiological studies using meta-analysis

The oral contraceptive pill (OCP) has been implicated as having a protective effect on the development of rheumatoid arthritis (RA). The results of 12 studies have now been reported and produced differing results and conclusions. Because of the discrepancy in results and the importance of the issue we undertook a review of the studies and performed a meta-analysis. In all, 9 independent studies satisfied the criteria for selection, 6 case-control design and 3 longitudinal. Using standard meta-analysis techniques, the overall pooled odds ratio for all the studies was 0.68 for the crude results (95% CI 0.58-0.78) and 0.73 for the adjusted results (95% CI 0.61-0.85). The graphical odd-man-out method produced a 94% interval of 0.70-0.72. The pooled odds ratio of the case-control studies was lower than for the longitudinal studies. However, subdividing studies by the type of case source produced a pooled odds ratio for studies using hospital-based cases of 0.49 (95% CI 0.39-0.63) which was considerably less than that of studies using population-based cases: 0.95 (0.78-1.16). This difference was unlikely to have explained by bias due to selection of controls. We suggest that OCP use may not have a "protective effect" on the development of RA but may prevent the progression to severe disease by modifying the disease process.

Health behavior and urinary tract infection in college-aged women

We conducted a case-control study to examine the associations between various behavioral risk factors and urinary tract infection among college-aged women. Cases were collected from a University Health Service, and were compared to Health Service controls and to a population-based control group. Sexual intercourse, diaphragm use, and urinating after sexual intercourse were each associated with urinary tract infection (UTI). The magnitude of the association of diaphragm use with UTI was reduced when urination habits around sexual intercourse were considered.

Mortality and immediate morbidity in term babies with low Apgar scores (Zimbabwe)

A retrospective study was undertaken to document immediate morbidity and mortality associated with low Apgar scores (5 or less) at 5 min in singleton term babies (37 weeks or more). From October 1986 to February 1987, 84 term babies had low Apgar scores, giving an incidence of 15/1000 live births. Overall mortality in these patients was 42%, and in those in whom Apgar scores remained 0-3 at 5 min, mortality was 77%. Evidence of severe-to-moderate hypoxic-ischaemic encephalopathy was noted in 44 (52%) and 17 (20%) failed to establish spontaneous respiration within the 1st few hours of life. Meconium aspiration syndrome was diagnosed in 29 (35%). A control group of 141 term babies with 5-min Apgar scores of 7 or more were identified and the presence of possible risk factors associated with low Apgar scores was assessed. Primiparity and prolonged second stages of labour in all parities were found to be significantly associated with low Apgar scores. Improved obstetric care and appropriate management of the newborn at delivery and in the neonatal period may help to reduce mortality and morbidity in some term babies.

Altered ciliary substructure in the endosalpinx in women using an IUCD

Fallopian tube segments were removed from 20 women undergoing sterilization by laparoscopy or laparotomy. Ten of these patients used an intrauterine contraceptive device (IUCD). The other 10 had used neither IUCD nor oral contraceptives and served as controls. The ciliary ultrastructure was examined by light- and transmission electron microscopy. The IUCD users had a significantly reduced ciliary length and less well oriented cilia, as compared with the control group. Also, the proportion of cilia with a ciliary crown structure was significantly smaller in IUCD users than in the non-users. The mechanism that may cause these alterations and their putative consequences are discussed.

The effect of the anti-progestin mifepristone (RU 486) on plasma prostaglandin metabolite levels in early pregnancy and its influence on pregnancy termination

The effect of a single dose of RU 486 (600mg) on prostaglandin metabolite levels has been studied over a 48 h period in 20 women undergoing medical termination of early pregnancy. The results were compared with controls of similar gestation who were treated surgically. The mean (SD) PGEM levels at 0 and 48 h in the RU 486 group were 13.7 (2.7) and 13.2 (2.2) pg/ml respectively, which was not significantly different from the values of 11.7 (1.1) and 11.3 (0.4) pg/ml measured in the control patients. Similarly the mean (SD) PGFM values of 22.3 (14.7) and 17.0 (7.2) pg/ml at 0 and 48 h were not significantly different from the corresponding control values of 21.9 (13.8) and 23.8 (7.2) pg/ml. In 10 of the study patients, there were no significant changes in PGEM and PGFM concentrations prior to and at 4, 24 and 48 h after RU 486 administration. Although all pregnancies were successfully terminated with the combination of RU 486 and subsequently a vaginal pessary containing PGE1, no stimulation of prostaglandin production could be demonstrated.

Breast feeding practices and maternal employment

Little information exists about the relationship between maternal employment and breast feeding practices and knowledge about lactation. The study was conducted on 318 employed and 299 non-employed women prospectively. Lactational practices were significantly influenced by employment status, with 81.9% non-employed vs. only 49.7% employed going in for exclusive breast feeds in the first 3 months (p less than .001). Correspondingly, 46.8% employed women started combined breast and bottle feeds from birth (p less than .001). Within the employed group, parity and social class did not significantly alter the infant feeding practices. Employed women were better informed about feeding and weaning as compared to their non-employed counterparts (36.8% vs. 18.4% p less than .001). Women from higher social class also tended to be more aware (59.8% vs. 7.2%: p less than .001). Multiparas had an edge over primiparas with respect to knowledge about lactation (36.1% vs. 20.1% p less than .01).

Induction of labour after fetal death: a randomized controlled trial of two prostaglandin regimens

A total of 85 women with antepartum fetal death between 14 and 42 weeks gestation was randomly assigned to one of two regimens of intravenous infusion of the prostaglandin analogue 16-phenoxy-17, 18, 19, 20-tetranor-PGE2-methylsulphonamide (sulprostone) for inducing labour. Women received either 1 microgram/min until delivery or the commonly recommended treatment of 1500 micrograms in 8 h followed by another, identical course of treatment if delivery did not occur within 24 h. The 1 microgram/min dose schedule used half the amount of prostaglandin and resulted in statistically significantly fewer gastrointestinal side-effects compared with the conventional treatment. All women were delivered vaginally and there were no differences in induction-to-delivery intervals between the two treatments. Sulprostone infused at a rate of 1 microgram/min resulted in a 50% chance of being delivered within 12 h and a 90% chance of being delivered within 24 h, with an overall frequency of side-effects of 20%.

Risk factors for deaths due to respiratory infections among Brazilian infants

In a population based case-control study, 127 Brazilian infants who died due to a respiratory infection were compared with 254 neighbourhood controls. The main risk factors associated with mortality were low socioeconomic status (including low levels of parental education) and--after adjustment for socioeconomic status--lack of breastfeeding, lack of supplementation with non-milk foods, crowding, the number of under-fives in the family, lack of a flush toilet, low birthweight, low weight-for-age and having a young mother. In a multivariate analysis, the variables found to be most closely associated with mortality were breastfeeding, education of the father, the number of under-fives, family income and birthweight. Having a low weight-for-age was also strongly associated with mortality but the retrospective nature of the study makes this finding difficult to interpret.

The effect of triphasic oral contraceptives on plasma lipids and lipoproteins

To determine the effect of triphasic oral contraceptives on plasma lipid transport, 150 nonsmoking women with normolipidemia, ages 18 to 35 years, were randomly assigned to receive one of three contraceptive formulations: (1) ethinyl estradiol, 30, 40, and 30 micrograms/day, each for 6, 5, and 10 days per menstrual cycle, and levonorgestrel, 50, 75, and 125 micrograms/day, each for 6, 5, and 10 days; (2) ethinyl estradiol, 35 micrograms/day for 21 days, and phased norethindrone, 500, 750, and 1000 micrograms/day each for 7 consecutive days; and (3) ethinyl estradiol, 35 micrograms/day for 21 consecutive days, and norethindrone, 500, 1000, and 500 micrograms/day for 7, 9, and 5 days, respectively. A control group consisting of 49 women taking a nonhormonal form of contraception was also included. After 6 months of oral contraceptive treatment, significant increases in plasma triglyceride (28% to 52%) and plasma apolipoprotein B levels (20% to 23%) were observed in each treatment group. The changes in total plasma cholesterol (3% to 10%) and low-density lipoprotein cholesterol values (0% to 11%) were less striking. Changes in total high-density lipoprotein cholesterol levels were statistically insignificant (-2% to -4%); however, high-density lipoprotein2 cholesterol levels decreased by 29% to 33% and high-density lipoprotein3 cholesterol levels increased by 20% to 23%. Concomitantly, plasma apoliporprotein A-1 values increased by 5% to 12%. No consistent significant differences among analyses were observed between and of the groups receiving different oral contraceptives for 6 months.

Determinants of infant and child mortality in rural Haryana

To identify the individual and household level variables associated with increased risk of mortality, 159 infant and 50 child deaths (cases) and equal number of age matched live infants and children (controls) and their families were studied in a rural area of Haryana. The social, economic, educational and environmental characteristics of the case and control families were similar. Increased risk of infant and child mortality was associated with maternal age less than 20 and more than 30 years, birth order 4th or higher, unclean cord care at the time of child birth, failure of breast feeding during the first 3 months of age, lack of immunizations, and previous infant or child death(s) in the family (Odds ratio greater than 2; P less than 0.05-0.01 by X2 test). An emphasis on the interventions directed at control of the above mentioned variables may prove most helpful in reducing infant and child mortality in a rural area.

Oral contraceptive use and liver cancer

The risk of liver cancer in relation to use of oral contraceptives was evaluated in a hospital-based case-control study conducted in five US cities from 1977 to 1985. Twelve new cases of liver cancer were identified in women aged 19-54 years; five controls selected from among patients hospitalized for acute conditions unrelated to oral contraceptive use were matched to each case on age (five-year categories), date of interview (three-year categories), and geographic location of the hospital. Among nine cases classified as having hepatocellular carcinoma, eight (89%) had used oral contraceptives; only 16 (36%) of 45 matched controls had used oral contraceptives. Among three other cases (two with cholangiocarcinomas and one with liver cancer of undetermined type), all had used oral contraceptives, compared with four of 15 matched controls. The results confirm the strong positive association between oral contraceptive use and hepatocellular carcinoma observed in earlier studies. Such an association is consistent with evidence that oral contraceptive use is associated with benign hepatic tumors in young women. However, the number of cases of liver cancer in the United States that are attributable to oral contraceptive use is probably small, because liver cancer is extremely rare in the United States.

Breast cancer and combined oral contraceptives: an Italian case-control study

The risk of breast cancer in relation to use of oral contraceptives was evaluated using data from a hospital-based case-control study from Northern Italy on 1517 cases below age 60 and 1351 controls admitted for acute diseases unrelated to any of the known or potential risk factors for breast cancer. The multivariate relative risk for ever vs. never users was 1.3 (95% confidence interval = 1.0-1.7). However, the risk was not related to duration of use: indeed the highest risk was observed among short-term users (less than 2 years), and the point estimate was 0.9 among users for 5 years or more. The elevated risk among short-term users, if not due to residual confounding or selection mechanisms, is probably explainable in terms of recall bias (i.e. more careful report of short or very short use by cases). No definite pattern was observed in relation to latency or recency of use, and the point estimates were 0.8 for women who had ever used the pill before age 25 and 0.8 for those who had ever used the pill before first full-term pregnancy. Thus, the study presents further reassuring information on the oral contraceptive/breast cancer debate. Its major limitation lies in the low prevalence of oral contraceptive users in Italy, with a consequently reduced statistical power, although, with the number of cases involved, it was possible to exclude a relative risk of 1.4 for long-term use or for ever use before first birth.

Breast milk fatty acids in mothers of children with atopic eczema

The total lipid fatty acid composition of mature breast milk has been analysed in a group of twenty-five mothers of children with atopic eczema, and compared with breast milk from twenty-two controls. Total lipids were extracted into chloroform-methanol (2:1, v/v) and the methyl esters prepared by alkalicatalysed trans-esterification were separated by gas-liquid chromatography and identified by comparison with standard fatty acid methyl esters. Results show that mothers of children with atopic eczema have a significantly greater proportion of linoleic acid, and a smaller proportion of dihomo-gamma-linolenic acid in their total breast milk lipid than the controls. Proportions of total derived fatty acids were similar between groups and there were no differences in the principal saturated and monounsaturated fats. It was concluded that mothers of children with atopic eczema have an abnormal breast-milk fatty acid composition. This supports previous evidence of a defect of conversion of linoleic acid into its long-chain polyunsaturated metabolites in the condition.

Serum concentrations of vitamin D metabolites in rachitic Libyan children

Twenty-two consecutive patients with rickets were studied in Benghazi, Libya. All were less than 2 years old. Rickets was associated with traditional cultural habits that limited sunshine exposure of the mothers and their infants, and with breast-feeding. Serum concentrations of the vitamin D metabolites 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D, and 24,25-dihydroxyvitamin D, and other parameters of mineral metabolism were typical of vitamin D deficiency disease, as was the biochemical and clinical response to treatment. Minimum safe serum levels of 25-OHD (20 nmol/L), and the serum levels of vitamin D metabolites in response to vitamin D treatment, were identical to previously obtained results from native Norwegian and Norwegian immigrant children with rickets, suggesting lack of racial differences in response to vitamin D. Fifty percent of the patients had adequate levels of vitamin D metabolites at the time of diagnosis, indicating that they had recently received oral vitamin D or cutaneous exposure to sunshine. Many cases of rickets in the area may, therefore, be spontaneously cured when the children's maturity allows adequate mobility and independence to achieve exposure to sunshine.

Pre- and postconception factors associated with sporadic heritable and nonheritable retinoblastoma

A matched case-control study of retinoblastoma was conducted by the Children's Cancer Study Group (CCSG) to investigate the hypotheses that postconception exposures affect the risk of the nonheritable (post-zygotic origin) form of this disease and that preconception exposures affect the risk of the sporadic heritable (prezygotic origin) form. Eligible cases were those patients with retinoblastoma diagnosed in 1982-1985 at any of the CCSG member hospitals. Cases were classified as familial heritable, sporadic heritable, or nonheritable based on family history, tumor laterality, and cytogenetic analysis. Telephone interviews of parents of 201 cases and their pair-matched controls selected by random digit dialing were completed. Analysis of possible risk factors for the 67 sporadic heritable cases and the 115 nonheritable cases was performed. (The 19 familial cases were excluded). For the nonheritable group, gestational exposure to X-ray [odds ratio (OR) = 2.3, P = 0.08] and morning sickness medication (OR = 2.8, P = 0.02) and low maternal educational level (OR = 5.5, P = 0.03) were associated with increased risk; anemia (OR = 0.3, P = 0.02) and multivitamin use (OR = 0.4, P = 0.03) during pregnancy and periconceptional use of barrier contraceptive (OR = 0.1, P = 0.02) or spermicide (OR = 0.2, P = 0.02) were associated with decreased risk. In the sporadic heritable group, observations included a negative association with multivitamins during pregnancy (OR = 0.2, P = 0.02) and nonsignificant positive associations with preconception gonadal X-ray (maternal, OR = 2.0, P = 0.30; paternal, OR = 1.8, P = 0.42) and older parental age (case-control difference 1.0-1.2 years, P = 0.24-0.27). Many of the associations support study hypotheses, although the possibility of recall bias and chance findings suggest cautious interpretation.

Regional distribution of human papillomavirus DNA and other risk factors for invasive cervical cancer in Panama

A population-based national cancer registry has documented strikingly different regional incidence rates of cervical cancer in the Republic of Panama. Such regional differences in disease rates could represent regional differences in the occurrence of risk factors, in particular, human genital papillomaviruses (HPV). This study enrolled newly diagnosed invasive cancer patients in the Republic of Panama over an 18-mo period. Behavioral risk factors were measured by interviewing cases and matched controls. In addition, DNA extracted from biopsies of the cancers was tested for HPV sequences. Early age at first coitus, multiple pregnancies, and nonparticipation in Pap smear screening programs were significant risk factors for cervical cancer in this population. These factors and low levels of education occurred more frequently among women residing in regions with higher cancer rates than women residing in the region with lower cancer rates. HPV DNA was detected most frequently (70%) among cases from the region with the lowest cancer rate (30 of 100,000) and least frequent (54%) among cases where the cancer rate was the highest (51 of 100,000). The observations suggest that risk factors other than HPV contribute to the differences in cervical cancer rates among women residing in various regions of Panama.

Intestinal permeability assessed with polyethylene glycols in children with diarrhea due to rotavirus and common bacterial pathogens in a developing community

Intestinal permeability was assessed with different-sized polyethylene glycols (PEG 400 and PEG 1,000) in small children with acute diarrhea. All children with acute diarrhea absorbed and excreted less PEG of all molecular sizes into the urine when compared with healthy control children (p less than 0.001). Children with acute rotavirus infection excreted significantly less PEG of all sizes than children with Shigella, Salmonella, and enteropathogenic Escherichia coli (EPEC) infection (p less than 0.001-0.01), suggesting a more severe mucosal lesion caused by rotavirus. In patients with severe malnutrition there was also a significant decrease in absorption of PEGs observed. In addition, malnourished patients with rotavirus diarrhea showed a pronounced decrease of PEGs in comparison with well-nourished patients. The ratio between the recovery of a large PEG molecule, 1,074 Da, and a small molecule, 370 Da, was utilized to assess the absorption of large molecules in relation to that of smaller ones. On applying this ratio, it was noted that the intestine in children with Shigella and EPEC infection was relatively more permeable to larger molecules than in healthy controls, while in rotavirus and Salmonella infection it was less permeable to larger molecules. In this study significant differences in the permeability characteristics were observed, suggesting etiology-specific effects on the mucosal barrier.

The contribution of previous induced abortion to tubal ectopic pregnancy

Data from a one year prospective study of thirty-one tubal ectopic pregnancies and ninety-three matched controls is presented. Compared with the controls, a history of induced abortion, was not only statistically significantly more frequent amongst the subjects (P less than 001) but was the Penultimate cyesis in 41.9% of ectopic cases as against 3.2% of the controls (P less than 001). Non-physicians provided 51.6% and 3.3% of induced abortions in the study and control groups respectively. Complications occurred in 51.6% of study population and 6.5% of controls. It is concluded that induced abortions created the predispotion to tubal implantation in the study population and therefore a reduction in the incidence of illegally induced abortion in the community can reduce the incidence of ectopic tubal gestation and tubal infertility.

Oral contraceptives and breast cancer: results from an expanded case-control study

The relationship between oral contraceptives and breast cancer was evaluated among 2,022 cases and 2,183 controls participating in a multicentre breast cancer screening programme. Ever use of oral contraceptives was not related to breast cancer risk (RR = 1.0, 95% CI 0.9-1.2), and no overall patterns of increasing or decreasing risks were observed according to the duration of use, or time since first or most recent use. Although we had no women with extended periods of oral contraceptive use early in life, no evidence of adverse effects attributable to short-term use before age 25, before first live birth or during the perimenopausal period were observed. Further, oral contraceptives did not interact with other breast cancer risk factors, except among those with a history of two or more breast biopsies (RR = 2.0). Analyses by stage of disease revealed that risk was related to the duration of oral contraceptive use: greater than or equal to 5 years use was associated with reduced risk for in situ cancer (RR = 0.59) and increased risks for invasive cancers (RR = 1.5 and 1.4 respectively for small and large lesions). These data suggest that oral contraceptive effects may vary by stage of disease, but provide no overall evidence of an association between oral contraceptives and breast cancer.

A case-control study of large bowel cancer and hormone exposure in women

Several lines of evidence indicate a potential role for hormonal or reproductive factors in the subsequent development of large bowel cancer in women. To evaluate the relationship between hormone exposure and large bowel cancer a case-control study was carried out in 18 Illinois hospitals. Female cases, ages 45-74 (n = 90), and controls (n = 208) were identified from an ongoing large bowel cancer study. Data were obtained from medical records, personal interviews, and a subsequent mail survey with a questionnaire specific to hormone usage. Menopausal estrogen use was found to be protective with respect to the subsequent development of large bowel cancer with an odds ratio of 0.6 (95% CI, 0.33-0.99). This effect remained after controlling individually for age at diagnosis, ever pregnant (yes/no), parity, age at first birth, hysterectomy with documented oophorectomy, cholecystectomy, and appendectomy. Simultaneous adjustment, using logistic regression, for age at diagnosis, parity, hysterectomy, and cholecystectomy resulted in an adjusted odds ratio for menopausal estrogen use and large bowel cancer of 0.5 (95% CI, 0.27-0.90). Subsite analysis revealed the protective effect to be strongest for the rectal cancer cases. These data support the hypothesis that exogenous hormones may alter the risk of large bowel cancer in women.

Microbial etiology of acute gastroenteritis in hospitalized children in Kuwait

During a period of 15 months 621 hospitalized children with acute gastroenteritis and 152 control children were investigated for etiologic agents of the disease. Putative enteropathogens were identified in 86% of the patients and 10% of the controls. Common viral agents associated with gastroenteritis among children included rotaviruses (45%) and enteric adenoviruses (4%). Bacterial pathogens infecting children were Salmonella serotypes (24%), enterotoxigenic Escherichia coli (9%), Campylobacter jejuni (7%), enteropathogenic E. coli (7%), Shigella (4%) and enterotoxigenic Aeromonas sp. (1%). The highest incidence of infections was observed in the 3- to 25-month age group. Mixed infections were observed in 12% of the patients. Viral gastroenteritis was clinically mild and of short duration. Upper respiratory tract infections, vomiting and watery stools were common features. In contrast bacterial gastroenteritis was more severe; stools were frequently bloody and abdominal pain, cramps, shock, convulsions and milk intolerance were predominant clinical features. Comparative analysis revealed differential features of bacterial and viral gastroenteritis which should help clinicians to make a tentative diagnosis and to start treatment early.

Oral contraceptive use and premenopausal breast cancer in Sweden and Norway: possible effects of different pattern of use

Different use of oral contraceptives (OCs) in relation to reproductive histories and age might explain the conflicting results found in studies from different countries of OC use and premenopausal breast cancer. A population-based case-control study in Sweden and Norway has been analysed separately for the two countries. The study consists of 317 Swedish and 105 Norwegian cases diagnosed 1984-1985 with 317 Swedish and 210 Norwegian controls. The results for each country separately are consistent with the joint analysis showing increased risk for breast cancer with increased duration of OC use with the exception of that for women with more than 15 years since first use. The relative risk of breast cancer for more than four years of use among Norwegian women was 0.6 (95% confidence internal (Cl), 0.2-1.8). In both countries there was a non-significant higher risk associated with increasing duration of use before first full-term pregnancy. Analyses for surveillance bias show no evidence of bias as explanation for the association between total duration of OC use and breast cancer.

Intra-uterine device failure: relation with drug use

A case-control study was undertaken in order to test the relationship between commonly used anti-inflammatory agents and the efficacy of intra-uterine devices (IUDs). Women who had become pregnant while wearing an IUD were compared with non-pregnant IUD users. 717 cases and 717 controls were recruited from the same medical practices. The case-women (IUD failure) used anti-inflammatory drugs, particularly aspirin, more frequently than the controls (p less than 0.001). In contrast, oral progestins, taken in the second part of the cycle (16th to 25th day) were more frequently used by the control-women group (p less than 0.001). Although cases and controls differed in age and gravidity (younger and higher, respectively) standardization for these items did not change the findings for drug use.