Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “First Birth Intervals”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed2003

Timing of pregnancy and the risk of epithelial ovarian cancer.

Recent animal studies suggest that progestagen-induced apoptosis of transformed ovarian surface epithelial cells may underlie the observed protective effect of pregnancy on the risk of ovarian cancer. Assuming that increasing numbers of cells are transformed with advancing age, we postulated that the benefits of pregnancy would be greater for older than younger women and tested this hypothesis in a population-based case-control study. We conducted interviews with 620 parous women, ages 18-79 years, with histologically confirmed incident ovarian cancer and 723 parous controls of the same age. Detailed information was collected on reproductive history, as well as hormonal exposures, smoking, medical history, and other factors. We estimated the relative risk of ovarian cancer associated with births at different ages through multiple logistic regression models. After adjusting for parity, older age at first and last births, and shorter time since last birth were all associated with significantly reduced risks of ovarian cancer. Age at first birth and time since last birth were not associated with ovarian cancer when adjusted for each other, whereas age at last birth remained strongly protective [odds ratio (OR), 0.57; 95% confidence interval (CI), 0.36-0.90] among women >35 years versus women less than 25 years. The effect was independent of total parity (per year of age among women with one birth: OR, 0.93; 95%CI, 0.87-1.01; among women with four or more births: OR, 0.96; 95%CI, 0.90-1.02). Our finding that ovarian cancer risk is reduced by pregnancy at older ages is further evidence that pregnancy confers a benefit beyond anovulation and is consistent with the theory that ovarian surface epithelial cell apoptosis induced by pregnancy hormones may be the underlying protective mechanism.

Adolescent↗
PubMed2006

Captive breeding of the white rhinoceros, Ceratotherium simum, and the Cape buffalo, Syncerus caffer.

Breeding records of 40 white rhinoceros and 155 Cape buffalo were analysed. Three rhinoceros cows bred in captivity, themselves conceived for the first time at 84, 87 and 95 months of age, respectively. Rhinoceros cows breed throughout the year. There is no evidence of a relationship between calving interval and month of birth. Calving intervals were normally distributed about the mean of 34 months and there were no significant differences between bulls, cows or sex of calf. There was no difference in the sex ratio of calves born to young cows nor older cows. The male:female ratio of the calves was 1:1. Younger cows did not have shorter birth intervals. Although captive Cape buffaloes breed throughout the year, there is a preponderance of births in midsummer. There was some evidence that larger cows produce heavier calves and that season of birth may influence birth weight. Male calves weighed 41.20 +/- 0.68 kg vs 39.00 +/- 0.73 kg (range 24-60 kg) for female calves but this difference was not significant. Calving intervals were normally distributed about the mean of 395 days and the male:female ratio of the calves was 1:1.2.

Age Factors↗
PubMed1989

[Characteristics of the ensemble organization of the human cerebral cortex from birth to 20 years of age].

When studying frontal, somatosensory and visual areas of the human cerebral cortex from birth up to 20 years of age in year-to-year intervals, it has been stated that by birth in neocortex all components of the neuron-glio-vascular ensembles are presented. They are not connected in their composition. During the first year of life the size of all types of neurons increases, long-axonal basket neurons differentiate, fasciculi of radial fibers become thick. By 3 years of life in the ensembles the neurons are definitely grouped as clusters. Sizes of spindle-like and satellite neurons increase; they distribute their axonal collaterals vertically, horizontally and in frontal-posterior direction. By 5-6 years of age the horizontal connection system becomes more complex at the expense of longitudinal growth and ramification of lateral and basal dendrites of the pyramidal neurons. In the section transversal areas occupied with cell groups increase. By 9-10 years of age the pyramidal neurons reach their greatest size. By 12-14 years of age the fibrillar component of the cortex increases considerably, inter- and intraensemble horizontal connections become more complex, the system of local connections becomes more plastic owing to development of short-axonal basket-like neurons. By 16-18 years of age the ensemble cortical organization in its main parameters of architectonics reaches the level specific for mature persons.

Adolescent↗
PubMed1995

Intracranial pressure and cerebral perfusion pressure in clinically normal equine neonates.

Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were determined in 8 clinically normal neonatal foals. After the foals oriented themselves and nursed the mares, they were sedated as necessary, and local anesthesia was provided for making the skin incisions. Using a technique similar to that used in human beings, an indwelling subdural catheter was placed to measure ICP. Carotid artery catheterization was used to measure arterial blood pressure. Cerebral perfusion pressure was calculated as the difference between mean arterial blood pressure and ICP. Intracranial pressure and CPP readings were taken twice during each 24-hour period, starting at 6 hours of age and continuing through 72 hours of age. Mean (+/- SD) ICP were 5.83 +/- 1.82, 8.81 +/- 2.06, and 9.55 +/- 1.55 mm of Hg (range, 2 to 15 mm of Hg), and mean CPP were 80.19 +/- 10.34, 75.30 +/- 10.86, and 76.80 +/- 12.59 mm of Hg (range, 50 to 109 mm of Hg) for each of the first three 24-hour periods after birth, respectively. All 8 foals had physical and neurologic examinations, CSF analysis, and computerized axial tomography evaluations. The foals manifested normal behavior during the interval of measurements, and adverse effects of the procedure were not detected during the monitoring period. Establishment of normal values for ICP and CPP are important to clinicians who have the opportunity to apply this technique for monitoring and evaluating neonatal foals with signs of CNS dysfunction.

Animals↗
PubMed2006

Pregnancies, breast-feeding, and breast cancer risk in the International BRCA1/2 Carrier Cohort Study (IBCCS).

BACKGROUND: Multiparity, young age at first childbirth, and breast-feeding are associated with a reduced risk of breast cancer in the general population. The breast cancer predisposition gene, BRCA1, regulates normal cell differentiation. Because mammary gland cells divide and differentiate during pregnancy, reproductive factors may influence breast cancer risk in BRCA1/2 mutation carriers differently than they do in noncarriers. METHODS: We performed a retrospective cohort study of 1601 women in the International BRCA1/2 Carrier Cohort Study cohort, all of whom carried a mutation in BRCA1 or BRCA2. Information on reproductive factors was obtained from a questionnaire. At the time of interview 853 subjects were classified with breast cancer. Data were analyzed by using a weighted cohort approach. All statistical tests were two-sided. RESULTS: There was no statistically significant difference in the risk of breast cancer between parous and nulliparous women. Among parous women, an increasing number of full-term pregnancies was associated with a statistically significant decrease in the risk of breast cancer (Ptrend = .008); risk was reduced by 14% (95% confidence interval [CI] = 6% to 22%) for each additional birth. This association was the same for carriers of mutations in either BRCA1 or BRCA2 and was restricted to women older than 40 years. In BRCA2 mutation carriers, first childbirth at later ages was associated with an increased risk of breast cancer compared with first childbirth before age 20 years (20-24 years, hazard ratio [HR] = 2.33 [95% CI = 0.93 to 5.83]; 25-29 years, HR = 2.68 [95% CI = 1.02 to 7.07]; > or = 30 years, HR = 1.97 [95% CI = 0.67 to 5.81]), whereas in BRCA1 mutation carriers, first childbirth at age 30 years or later was associated with a reduced risk of breast cancer compared with first childbirth before age 20 years (HR = 0.58 [95% CI = 0.36 to 0.94]). Neither history of interrupted pregnancies (induced abortions or miscarriage) nor history of breast-feeding was statistically significantly associated with the risk of breast cancer. CONCLUSIONS: BRCA1 and BRCA2 mutation carriers older than 40 years show a similar reduction in breast cancer risk with increasing parity as non-carriers.

Abortion, Induced↗
PubMed1987

Prospective appraisal of complaints of adverse reactions to foods in children during the first 3 years of life.

To examine the natural history of adverse reactions to foods, 480 children were followed prospectively from birth to their third birthdays. Foods thought to be causing symptoms were evaluated by elimination of suspected foods, open challenges, and double-blind food challenges. Foods producing symptoms were reintroduced into the diet at 1- to 3-month intervals until the symptoms no longer occurred. Of the 480 children completing the study, 28% were thought to have symptoms produced during food ingestion, but in only 8% were these reactions reproduced (excluding fruit and fruit juices). During the first year of life 80% of the initial complaints occurred. The most striking finding was the brief duration during which reactions could be reproduced. The majority of foods were replaced in the diet within 9 months of their incrimination. A long list of foods was reported to produce many symptoms, but only a few foods reproducibly evoked gastrointestinal and skin symptoms, with respiratory symptoms being infrequent. Of great interest was that 75 children were reported to react to fruit or fruit juice, and 56 of these children had reproducible symptoms. This study has found that most food reactions occur during the first year of life, but rechallenge at regular intervals has shown that the food can be reintroduced into the diet by the third year without risk. Almost all reactions that were reproduced appear to be non-immunoglobulin E mediated.

Animals↗
PubMed2006

Neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight.

OBJECTIVE: To assess the risk of neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight. STUDY DESIGN: Data from a historical cohort study based on a twin registry in the US (1995-1997) were used. Multivariate logistic regression was used to control for maternal age, race, marital status, cigarette smoking during pregnancy, parity, medical complications, gestational age, and other confounders. RESULTS: A total of 86 041 vertex-vertex second twins were classified into two groups: second twins delivered by cesarean section after cesarean delivery of first twin (C-C) (43.0%), second twins whose co-twins delivered vaginally (V-X) (57.0%). In infants of birth weight>or=2500 g group, the risks of noncongenital anomaly-related death (adjusted odds ratio (aOR): 4.64, 95% confidence interval (95% CI): 1.90, 13.92), low Apgar score (aOR: 2.39, 95% CI: 1.43, 4.14), and ventilation use (aOR: 1.31, 95% CI: 1.18, 1.47) were higher in the V-X group compared with the C-C group. No asphyxia-related neonatal deaths occurred in C-C group, whereas the incidence of this death was 0.04% in the V-X group. CONCLUSION: The risks of neonatal mortality and morbidity are increased in vertex-vertex second twins with birth weight>or=2500 g whose co-twins delivered vaginally compared with second twins delivered by cesarean section after cesarean delivery of first twin.

Adult↗
PubMed2003

Pregnancy outcome in liver transplant recipients.

OBJECTIVE: To evaluate pregnancy course, complications, and outcomes in liver transplant recipients. METHODS: We conducted a retrospective review of 38 pregnancies conceived between 1992 and 2002 in 29 women who underwent liver transplantation at Mount Sinai Medical Center. RESULTS: The most common primary liver disease was autoimmune hepatitis. All patients were on immunosuppressive regimens that included cyclosporine A or tacrolimus. There were four spontaneous first-trimester abortions and ten first-trimester terminations for worsening liver function. The interval from transplantation to pregnancy was shorter in the group that had abortions and terminations (24.4 +/- 24.3 months) as compared with the group that had live births (47.8 +/- 28.7 months), P =.02. There were 24 live births to 20 patients. The mean gestational age at delivery was 36.4 weeks, and the mean birth weight was 2762 g. Pregnancy complications included preeclampsia (20.8%), chronic hypertension (20.8%), hemolysis, elevated liver enzymes, low platelets syndrome (8.3%), creatinine 1.3 mg/dL or more (25.0%), anemia (33.3%), diabetes (37.5%), cesarean delivery (45.8%), preterm birth less than 37 weeks (29.2%), intrauterine growth restriction (16.7%), and biopsy-proven graft rejection during pregnancy (16.7%). There were no intrauterine or neonatal deaths. All 5-minute Apgar scores were greater than 7. Four minor congenital anomalies were noted. Before 1997, there were five maternal deaths, 10-54 months after pregnancy. Pregnancy complications in our population were more common in those patients who delivered from 1992 to 1997 than in those who delivered from 1998 to 2002. CONCLUSION: Pregnancy planned at least 2 years after liver transplantation with stable allograft function can have excellent maternal and neonatal outcome.

Abortion, Spontaneous↗
PubMed2001

Risk of birth defects in a population exposed to environmental lead pollution.

To investigate the relation between environmental lead and risk of birth defects in humans, we examined the prevalence at birth of congenital anomalies in an industrial area of northern Italy heavily polluted with lead. Through a population-based registry of birth defects, we identified anomalies diagnosed during three consecutive periods characterized by decreasing environmental lead exposure, 1982-1986, 1987-1990 and 1991-1995. In the lead-polluted area, we observed an excess risk of cardiovascular defects which decreased from 2.59 [95% confidence interval (CI) 1.68-3.82] in the first period to 1.18 (95% CI 0.62-2.06) and 0.97 (95% CI 0.57-1.54) in the subsequent periods. We also found an excess risk of oral clefts and musculoskeletal anomalies, with decreasing trends over time. We could not identify homogeneous patterns of temporal variation for other congenital anomalies, neither did we detect cases of neural tube defects. These results appear to support an association between severe parental lead exposure and specific birth defects.

Congenital Abnormalities↗
PubMed2004

Anticipation of age at onset in multiple sclerosis: a Sardinian cohort study.

BACKGROUND: To assess the temporal trend in multiple sclerosis (MS) onset during the last 50 years in Sardinia, Italy. METHODS: The authors used a cohort study to assess age at onset in 1,513 MS patients at the MS clinic in Cagliari, all born and living in Sardinia. They also assessed age at onset in 41 pairs of familial patients from two generations and 78 pairs of affected sibs. Each familial couple was paired with three couples of sporadic patients born in the same year as the familial ones. The time interval between the first symptoms and diagnosis was analyzed in first and second-diagnosed patients from both familial and control couples. RESULTS: Mean age at onset progressively decreased from the most remote to the most recent decade of birth (log-rank test 778.27, p < 0.0001), being 41 years in the former decade and 22 years in the latter. A genetic influence was ruled out, because the younger member of familial patients coming from two generations had onset 14.0 years earlier than the older one (p < 0.0001), as in the paired control couples (11.6 years, p < 0.0001). Moreover, mean onset in younger sibs was 3.4 years earlier than in older ones (p = 0.01), similar to that of control couples (4.1 years, p < 0.0001). CONCLUSION: Age at onset decreases progressively from older to younger generations in Sardinian MS patients. Nongenetic but recent widespread environmental changes might contribute to shortening of the preclinical phase-overt disease interval.

Adolescent↗
PubMed2003

Impact of low birthweight on subsequent fertility: population-based register study.

Adverse birth outcomes may influence a family's wish for additional children. We investigated the influence of low birthweight in live births on subsequent fertility, and estimated secular trends of such an effect in a population-based cohort study of births arranged in consecutive sibship records in the Medical Birth Registry of Norway. We included births of order one to seven to all 587 785 mothers in Norway who had a first singleton birth in 1967-91. Associations between birthweight in 1 158 072 surviving index births of order one to six, 1967-91, and subsequent fertility (probability of another birth), 1967-97, were estimated as fertility ratios in Cox regression analysis. Giving birth to a live infant weighing < 3000 g had a negative effect on subsequent fertility, increasingly strong for decreasing birthweight. Low birthweight (<2500 g) was associated with a fertility ratio of 0.88 [95% confidence interval 0.87, 0.89]. This negative impact was stronger if the mother had also given birth to surviving children of low birthweight previously, particularly if combined with caesarean section in the most recent birth. The negative fertility effect of low birthweight grew slightly stronger between 1967 and approximately 1980, according to year of first birth. This trend paralleled reduced population fertility in the same period. The moderate negative impact of giving birth to a live infant of low birthweight on subsequent fertility could result from the combination of reduced wish for additional children and biological subfertility.

Female↗
PubMed1995

Parasuicide in the first postnatal year.

Data were collected on a consecutive 6 month sample of women aged 15-44 years attending their catchment area Casualty Department because of parasuicide. Information included age and childbirth within the previous year. Using this information and catchment area data on population size and births, an odds ratio for parasuicide in postnatal as compared to non-postnatal women was calculated. Five of 131 study subjects had delivered a baby in the previous 12 months. The odds ratio was calculated to 0.43 (95% confidence interval 0.17-0.95). These findings suggest that the rate of parasuicide in the first postnatal year is low despite the high rate of psychiatric morbidity at this time. The result supports previous findings on suicide and suggests that postnatal women, despite their high rates of psychiatric disorder, are protected against fatal and non-fatal self harm. The implications for postnatal and suicide prevention services are discussed.

Adolescent↗
PubMed1994

Abuse during pregnancy: effects on maternal complications and birth weight in adult and teenage women.

OBJECTIVE: To determine the incidence of physical and sexual abuse in a sample of adult and teen pregnant women and to determine the effect of abuse on birth weight. METHODS: One thousand two hundred three African-American, Hispanic, and white urban female residents were screened for abuse on their first prenatal visit and in the second and third trimesters. Infant birth weight was obtained by record review. RESULTS: Abuse during pregnancy was reported by 20.6% of teens and 14.2% of the adult women (P < .01). Both abused teens and adults were more likely than nonabused women to enter prenatal care in the third trimester (21.9 versus 7.5%, P = .001 for teens; 15.8 versus 8.7%, P = .007 for adults). For the aggregate sample of 1203 women, abuse during pregnancy was a significant (P < .05) risk for low birth weight (LBW), as well as low maternal weight gain, infections, anemia, smoking, and use of alcohol or drugs. Using Institute of Medicine risk factors for LBW, abused adults were at significantly greater risk for poor obstetric history, short inter-pregnancy interval, infections, anemia, smoking, and alcohol or drug usage. Abused teens had a significantly greater risk for poor weight gain, first- or second-trimester bleeding, smoking, and alcohol or drug use. CONCLUSIONS: One in five teens and one in six adult women experienced abuse during pregnancy. Abuse is related to LBW and late entry into prenatal care. Abuse can be documented readily with a short abuse assessment screen and interventions then initiated.

Adolescent↗
PubMed2002

Regression-based reference limits for urinary amino acids in a pediatric population.

Age-related variation of the urinary excretion of amino acids has been widely reported. Instead of the conventional reference intervals, continuous reference limits might be a more practical approach during periods of rapid changes such as infancy or childhood. Regression-based reference limits have been produced for the urinary excretion of 23 amino acids analyzed in 148 healthy individuals from 0 to 12 years of age. Urinary excretion was modeled as a function of age by two parametric procedures: the polynomial and the piece-wise linear regression methods. Likewise, age-specific standard deviation was estimated by the regression of the absolute values of the residuals on age. Residual analysis was employed to select the best-fitting model and the 95% reference limits, and their 95% confidence intervals were calculated and plotted against the raw data. The urinary excretion of 19 amino acids decreased rapidly during the first year of life with a further slow decline thereafter. These amino acids fit better the piecewise model. The other four amino acids displayed a steady decrease in the urinary excretion from birth to puberty, and the excretion patterns fit better the quadratic or linear model. Fifteen amino acids showed a significant change in standard deviation with age. Regression-based reference limits differed consistently from conventional limits (<3 years) and narrower confidence intervals were obtained throughout the entire period studied. Avoiding partitioning gave rise to smoothly changing limits. Therefore, such alternative way of presenting amino acid reference limits may facilitate the follow-up of patients with inborn errors of amino acid metabolism.

Age Factors↗
PubMed2005

Fifty years of chimpanzee demography at Taronga Park Zoo.

There has been a captive Pan troglodytes colony at Taronga Park Zoo in Sydney, Australia, since the mid-1930s. Demographic data on these animals were first analyzed in 1986; however, further information collected for 15 years since then is now available. The reproductive histories of 33 females in the colony have been recorded, and these data form the largest collection of captive chimpanzee data from a setting that has involved natural breeding conditions since the mid-1960s. These data were analyzed in conjunction with data from wild populations to establish the degree of variability present within chimpanzee reproductive parameters, and to identify which distinctive life history characteristics persist in well-provisioned, natural-fertility populations. The age at first birth for the chimpanzee females is 9.8 yr on average (n=16), which is 1-4.8 yr earlier than the average for wild populations. In line with this accelerated reproduction, birth intervals are also significantly shorter than those in noncaptive chimpanzee populations. The median birth interval for all surviving infants (based on a Kaplan-Meier survival analysis) is 49 months (n=43) compared to 62+ months for wild groups. At the same time, infant mortality remains high. The data confirm distinctive features of the life history of common chimpanzees, including later maturation, long birth intervals, a relatively invariant fertility schedule, and high juvenile mortality. However, aspects of both fertility and mortality are significantly related to social circumstances, indicating that in common chimpanzees, as in humans, life history characters may represent ecological and social adaptations rather than species-fixed characteristics.

Age Factors↗
PubMed2003

Gastric electrical activity in normal neonates during the first year of life: effect of feeding with breast milk and formula.

BACKGROUND: To evaluate the effect of feeding with milk on the gastrointestinal tract, we studied gastric electrical activity in 27 healthy fullterm newborns (15 formula-fed newborns and 12 breast-fed newborns) during the first 6 months of life. METHODS: Three-hour electrogastrography (EGG) recordings were performed, using portable equipment, from the third to fifth day after birth until 6 months, at 3-month intervals. The EGG parameters were calculated as raw and integrated data, the latter as AUC of the whole postprandial period. RESULTS: There was a significant difference in the fasting 3-cpm activity between the two groups (repeated measures analysis of variance [ANOVA] P=0.02; multiple comparisons: formula milk at birth vs breast milk at birth P<0.001). In addition, a significant change in the percentage of postprandial bradygastria was found at 6 months, 1 month after weaning (repeated measures ANOVA, P=0.01; multiple comparisons: formula milk at 6 months vs formula milk at 3 months, P=0.03, formula milk at 6 months vs formula milk at birth, P=0.02; breast milk at 6 months vs breast milk at 3 months, P=0.03, breast milk at 6 months vs breast milk at birth P=0.02). CONCLUSIONS: An adult-like gastric 3-cpm activity can be observed in breast-fed newborns in contrast to formula-fed ones, probably as an effect of colostrum. The high bradygastria percentage recorded at 6 months of life might be the result of an increased low-frequency component of the EGG signal because of the transition to a mixed diet.

Child Development↗
PubMed2005

Timing and intensity of early fevers and the development of allergies and asthma.

BACKGROUND: Early childhood fevers appear to protect against later allergies and asthma. What is not known is the time in which fevers exert this effect and whether the degree of temperature increase is important. OBJECTIVE: We sought to examine the relationship between the time and degree of early fevers and later allergies and asthma. METHODS: Eight hundred thirty-five children from southeast Michigan were enrolled at birth. Clinic records from their first 2 years were abstracted for episodes of fever. At age 6 to 7 years, children underwent allergy testing. We examined fevers occurring within 6-month intervals in the first 2 years of life and outcomes at age 6 to 7 years. The primary outcome measures were allergic sensitization, asthma, asthma with allergic sensitization, and asthma without allergic sensitization. RESULTS: In the unadjusted analysis each episode of fever between 7 and 12 months of age was associated with a lower odds of allergic sensitization (odds ratio [OR], 0.71; 95% CI, 0.54-0.93) and asthma with allergic sensitization (OR, 0.43; 95% CI, 0.21-0.90) at age 6 to 7 years. Likewise, every 1 degrees C increase in the maximum temperature between 7 and 12 months was associated with a lower odds of allergic sensitization (OR, 0.77; 95% CI, 0.61-0.96) and asthma with allergic sensitization (OR, 0.62; 95% CI, 0.40-0.94). After adjusting for potential confounders, each episode of fever between 7 and 12 months was associated with a lower likelihood of asthma with allergic sensitization (adjusted OR, 0.33; 95% CI, 0.11-0.94) at age 6 to 7 years. CONCLUSIONS: Both the timing and intensity of childhood fevers appear to be important factors in the development of allergies and asthma.

Asthma↗
PubMed1997

Non-dietary factors as risk factors for breast cancer, and as effect modifiers of the association of fat intake and risk of breast cancer.

To assess more precisely the relative risks associated with established risk factors for breast cancer, and whether the association between dietary fat and breast cancer risk varies according to levels of these risk factors, we pooled primary data from six prospective studies in North America and Western Europe in which individual estimates of dietary fat intake had been obtained by validated food-frequency questionnaires. Based on information from 322,647 women among whom 4,827 cases occurred during follow-up: the multivariate-adjusted risk of late menarche (age 15 years or more compared with under 12) was 0.72 (95 percent confidence interval [CI] = 0.62-0.82); of being postmenopausal was 0.82 (CI = 0.69-0.97); of high parity (three or more births compared with none) was 0.72 (CI = 0.61-0.86); of late age at first birth (over 30 years of age compared with 20 or under) was 1.46 (CI = 1.22-1.75); of benign breast disease was 1.53 (CI = 1.41-1.65); of maternal history of breast cancer was 1.38 (CI = 1.14-1.67); and history of a sister with breast cancer was 1.47 (CI = 1.27-1.70). Greater duration of schooling (more than high-school graduation compared with less than high-school graduation) was associated significantly with higher risk in age-adjusted analyses, but was attenuated after controlling for other risk factors. Total fat intake (adjusted for energy consumption) was not associated significantly with breast cancer risk in any strata of these non-dietary risk factors. We observed a marginally significant interaction between total fat intake and risk of breast cancer according to history of benign breast disease; with fat intake being associated nonsignificantly positively with risk among women with a previous history of benign breast disease; no other significant interactions were observed. Risks for reproductive factors were similar to those observed in case-control studies; relative risks for family history of breast cancer were lower. We found no clear evidence in any subgroups of a major relation between total energy-adjusted fat intake and breast cancer risk.

Breast Neoplasms↗