Perinatal factors and mortality from breast cancer

Perinatal factors, female breast cancer, and associated risk factors in Puerto Rico: evidence from the Atabey epidemiology of breast cancer study

PURPOSE

There is increasing evidence that exposures in utero and in infancy impact breast cancer risk. No previous studies have evaluated these associations among women in Puerto Rico.

METHODS

In a population-based case-control study of breast cancer epidemiology in the San Juan metropolitan area in Puerto Rico, we examined the association of early life factors with breast cancer risk and breast cancer risk factors. Both cases (n = 315) and controls (n = 348) completed interviewer-administered questionnaires, including self-reported birth country, birthweight, and history of having been breastfed. Comparisons of characteristics of those with and without the early life factors were made with t-tests or chi-squared tests; associations between early life factors and breast cancer risk were estimated with unconditional logistic regression adjusting for age, education, body mass index (BMI), age at menarche, parity, and menopausal status.

RESULTS

Women who had been breastfed tended to have higher adult body mass index (BMI), higher education, and lower parity (p < 0.05). Higher birthweight was associated with higher adult BMI and lower educational attainment (p < 0.05). Those born outside of Puerto Rico or the US were more likely to have higher educational attainment and earlier age at menarche than those born within Puerto Rico or the US (p < 0.05). We found no significant associations between any of the early life factors and breast cancer risk.

CONCLUSION

We did not find evidence of an association of early life factors with breast cancer risk among women in Puerto Rico.

The Relationship of Pre and Early Postnatal Risk Factors with Breast Cancer

Background:

Breast cancer (BC) is the most prevalent cancer in Iranian women and the fifth most common cause of cancer-related death in Iran. Risk factors in the adult life may act during fetus life and after delivery. We conducted a case–control study to find out the relation of in utero and early life exposure and risk of BC.

Methods:

A structured questionnaire that covered demographic criteria and BC risk factors in utero was completed for case (732 cases) and control (584 subjects) groups, matched in terms of demographic variants, reproductive issues and socioeconomic status. Odds ratio (OR) and 95% confidence intervals (CI) were computed as measures of association from the logistic models.

Results:

Having been breast feed for more than 19-24 month (P<0.001, OR 0.03, CI 0.004-0.21) is protective and positive family history of mother (P-value= 0.009, OR 3.4) is a risk factor for BC in adult.

Conclusion:

There is increasing recognition that condition in utero is important for later risks in breast. Emerging evidence suggests an association between intrauterine status and women prenatal condition and their subsequent risk of developing breast cancer. this is the first Iranian study assessing prenatal factors and breast cancer risk in the EMR and it should be followed by the larger group of cases and controls in the future.

Birth size and cancer prognosis: a systematic review and meta-analysis

There is an established link between birth parameters and risk of adult-onset cancers. The Developmental Origins of Health and Disease concept provides potential underlying mechanisms for such associations, including intrauterine exposure to endogenous hormones (androgens and estrogens), insulin-like growth factors, etc. However, there is conflicting evidence on the association between birth parameters and the cancer mortality risk. Therefore, we aimed to review and analyse the available data on the association linking birth weight and birth length with cancer mortality. Eleven studies were identified, published until April 2019. A significant association between birth weight and the prognosis of cancer (overall) was found (relative risk, RR 1.06, 95% confidence interval, CI: 1.01, 1.11), with low heterogeneity (I2 = 27.7%). In addition, higher birth weight was associated with poorer prognosis of prostate cancer (RR 1.21, 95% CI: 1.02, 1.44). However, the association of birth weight with breast cancer mortality risk in women was not significant (RR 1.16, 95% CI: 0.93, 1.44), which might be due to high statistical heterogeneity (I2 = 67.9%). Birth length was not associated with cancer mortality risk (RR 1.0, 95% CI: 0.90-1.11). It might be inferred that birth parameters are not associated with cancer mortality as strongly as with the risk of developing cancer. Also, the association between birth parameters and cancer mortality risk is not uniform and varies according to its subtypes, and study characteristics/design. This highlights the need for further prospective studies.

Circulating maternal and umbilical cord steroid hormone and insulin-like growth factor concentrations in twin and singleton pregnancies

In addition to being associated with a higher risk of complications during pregnancy, twinning may also be a proxy for altered hormonal exposure for mothers and twin offspring, with implications for their health later in life. We compared maternal and fetal steroid hormone and insulin-like growth factor concentrations between singleton (n=62) and twin (n=41) pregnancies. Maternal concentrations of androgens, estrogens, insulin-like growth factor (IGF)-1, IGF-binding protein (BP)-3 and prolactin were quantified during the third trimester and at delivery, as well as in the fetal circulation at birth. Geometric means accounting for gestational age were calculated for hormone concentrations and compared between matched twin and singleton pregnancies. Most maternal hormone concentrations were modestly higher in twin than in singleton pregnancies in the third trimester (ranging from 8.3% for IGF-1 to 17.1% for estradiol) and at delivery (ranging from 11.1% for IGFBP-3 to 15.2% for estriol). Cord serum hormones were generally similar in twin and singleton pregnancies, except for IGFBP-3, which was 200% lower in twins. The modest differences in maternal hormones in late gestation seem unlikely to explain alterations in hormonally related disease risk in mothers of twins compared with singletons. The large deficit of IGFBP-3 in the fetal circulation of twins at birth may allow for sufficient concentrations of IGF-2 for growth and development in an environment of shared nutritional resources.

Breast cancer and exposure to tobacco smoke during potential windows of susceptibility

PURPOSE

An association between smoking and breast cancer is unresolved, although a higher risk from exposure during windows of susceptibility has been proposed. The objective of this prospective study was to evaluate the association between tobacco smoke and breast cancer with a focus on timing of exposure, especially during early life.

METHODS

Sister study participants (n = 50,884) aged 35-74 were enrolled from 2003 to 2009. Women in the United States and Puerto Rico were eligible if they were breast cancer-free but had a sister with breast cancer. Participants completed questionnaires on smoking and environmental tobacco smoke (ETS) exposure. Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for breast cancer risk.

RESULTS

During follow-up (mean = 6.4 years), 1,843 invasive breast cancers were diagnosed. Neither active smoking nor adult ETS was associated with breast cancer risk. However, never smoking women exposed to ETS throughout their childhood had a 17% higher risk of breast cancer (95% CI 1.00-1.36) relative to those with no exposure. In utero ETS exposure was also associated with breast cancer (HR = 1.16, 95% CI 1.01-1.32) and the HR was most elevated for women born in earlier birth cohorts (<1940, HR = 1.44, 95% CI 1.02-2.02; 1940-1949, HR = 1.28, 95% CI 1.01-1.62).

CONCLUSION

In utero ETS and ETS exposure during childhood and adolescence were associated with increased risk of breast cancer and associations varied by birth cohort.

Do firstborn children have an increased risk of ADHD?

OBJECTIVE

Although previous reports have found no birth-order influence on ADHD risk, the authors hypothesize that being the firstborn is a risk factor for developing ADHD.

METHOD

They selected all of the currently treated ADHD outpatients (n = 748) from our database. Families with adopted sons, nonnuclear families, and families with only one child and with sons (affected or unaffected) younger than 6 or older than 18 years were excluded. A total of 181 families with 213 ADHD sons met the inclusion criteria. We used all siblings without a clinical diagnosis of ADHD and who had no contact with our service as our unaffected controls (n = 173).

RESULTS

The bivariate analysis showed that ADHD was associated with birth order and that firstborn children had nearly twice the ADHD risk of children with other birth orders.

CONCLUSION

birth order can be an ADHD risk factor in clinical samples.

Birth weight and other prenatal factors and risk of breast cancer in Asian-Americans

Little is known about the role of birth weight and other prenatal factors in the etiology of breast cancer in Asian-Americans. We investigated the relation between birth weight and other prenatal factors and breast cancer risk in a population-based case-control study in Los Angeles County that included 2,259 Asian-American women with incident, histologically confirmed breast cancer and 2,019 control women, who were frequency matched to cases on age, Asian ethnicity, and neighborhood of residence. Breast cancer risk nearly doubled (odds ratio (OR) = 1.97, 95% confidence interval (CI) = 1.15-3.39) among those with high (≥ 4000 g) birth weight compared to those with low (<2500 g) birth weight after adjusting for age at menarche, parity, adult body mass index, and other covariates. Risk increased 8% per 500 g increase in birth weight (P trend = 0.10). We observed a significant relationship between birth weight and age at menarche in both cases and controls. Mean birth weight was higher (2948 g) for control women who had early menarche (age ≤ 11 years) compared to those who had menarche late (age ≥ 15 years) (2807 g) (P trend = 0.016); results were similar among case patients (P trend = 0.020). Older maternal age was also a risk factor; risk increased by 6% (95% CI = 1.01-1.12) per 5 years increase in maternal age with adjustment for parity and other risk factors. Our results support the hypothesis that high birth weight and older maternal age at pregnancy may have contributed to the rising breast cancer incidence in Asian-Americans.

Reversed urban-rural differences in breast cancer mortality (China, 2002-2008)

The purpose of this study was to examine the urban-rural difference in breast cancer mortality between 2002 and 2008 in China. A longitudinal analysis of mortality data was performed. Mortality data were extracted from Chinese Health Statistics Yearbook. Linear regression was used to examine the statistical significance of linear trend in mortality rates. The percent change in rates was used to measure the linear trend, which was calculated as regression coefficient × 100 × 6 divided by the rate of 2002. Between 2002 and 2008, the mortality from breast cancer increased by 201% among urban women (P < 0.05) while among rural women the rate did not show the significant increase, thus resulting in a reversed urban-rural difference (from -2.3/100,000 population in 2002 to 3.6 in 2008). Subgroup analysis showed that the reversed urban-rural difference was completely due to substantial increases among urban women aged 55-59 years and aged 75 years and above. In addition, significant decreases of breast cancer mortality were observed in urban women aged 35-49 years and in rural women aged 35-39 years (P < 0.05). The reversed urban-rural difference in breast cancer mortality during 2002-2008 is primarily caused by the increases among elderly urban women. Further studies are needed to understand the increases and to develop cost-effective interventions for elderly urban women in China.

Perinatal factors reported by mothers: do they agree with medical records?

As perinatal events have been linked with diseases of later onset, epidemiological studies on child development and adult health require information on the perinatal period. When national neonatal registers do not exist, review of medical records may be impractical. However, neonatal information could be obtained by asking mothers to complete a postal questionnaire using data from the Personal Child Health Record (PCHR). We assessed agreement between medical records and mothers' reports for information on delivery and the newborn's condition at birth, based on the PCHR, a short time after delivery. Of 711 women giving birth in 3 French hospitals and invited to participate in the study, 580 (82%) completed a postal questionnaire 6 weeks after delivery, copying the data recorded in the PCHR when available. Information on pregnancy, delivery and the newborn's health at birth was independently extracted from medical records by physicians of the maternity departments. Agreement between medical records and maternal reports for a range of perinatal factors was assessed in 580 newborn-mother dyads using kappa coefficients. Agreement was excellent for first and second stages of delivery, gestational age, birth weight, birth size and head circumference (kappa coefficients 0.80-1.00) and good for hospitalization during pregnancy, but poor for Apgar scores. With this exception, mothers' reports appeared reliable when compared with medical records. As PCHRs exist in most developed countries, this approach could be used in epidemiological studies on child development to increase the reliability of mothers' reports of their newborn's condition at birth.

Intrauterine environments and breast cancer risk: meta-analysis and systematic review

Introduction

Various perinatal factors, including birth weight, birth order, maternal age, gestational age, twin status, and parental smoking, have been postulated to affect breast cancer risk in daughters by altering the hormonal environment of the developing fetal mammary glands. Despite ample biologic plausibility, epidemiologic studies to date have yielded conflicting results. We investigated the associations between perinatal factors and subsequent breast cancer risk through meta-analyses.

Methods

We reviewed breast cancer studies published from January 1966 to February 2007 that included data on birth weight, birth order, maternal age, gestational age, twin status, and maternal or paternal smoking. Meta-analyses using random effect models were employed to summarize the results.

Results

We found that heavier birth weights were associated with increased breast cancer risk, with studies involving five categories of birth weight identifying odds ratios (ORs) of 1.24 (95% confidence interval [CI] 1.04 to 1.48) for 4,000 g or more and 1.15 (95% CI 1.04 to 1.26) for 3,500 g to 3,999 g, relative to a birth weight of 2,500 to 2,599 g. These studies provided no support for a J-shaped relationship of birthweight to risk. Support for an association with birthweight was also derived from studies based on three birth weight categories (OR 1.15 [95% CI 1.01 to 1.31] for ≥4,000 g relative to <3,000 g) and two birth weight categories (OR 1.09 [95% CI 1.02 to 1.18] for ≥3,000 g relative to <3,000 g). Women born to older mothers and twins were also at some increased risk, but the results were heterogeneous across studies and publication years. Birth order, prematurity, and maternal smoking were unrelated to breast cancer risk.

Conclusion

Our findings provide some support for the hypothesis that in utero exposures reflective of higher endogenous hormone levels could affect risk for development of breast cancer in adulthood.