Birth weight in relation to endometrial and breast cancer risks in Swedish women

An examination of birth weight in a Swedish cohort study of 38,566 women showed no significant association between birth weight and endometrial cancer, but supported a protective role for low birth weight for premenopausal breast cancer.     

Birth weight and risk of breast cancer in a cohort of 106,504 women

The possible association between prenatal factors and breast cancer has been discussed for more than a decade. Birth weight has been used commonly as a proxy measure for intrauterine growth. Whereas some previous studies have found support for an association between birth weight and breast cancer, others have been inconclusive or found no association. We investigated the relationship between birth weight and risk of female breast cancer in a cohort of 106,504 Danish women. Birth weights were obtained from school health records on girls born between 1930-1975. Information on breast cancer came from linking the cohort with the Danish Cancer Registry and the Danish Breast Cancer Cooperative Groups Registry. A total of 2,334 cases of primary breast cancer were diagnosed in the cohort during 3,255,549 person-years of follow-up among women with birth weight between 500-6,000 g. Of these, 922 (40%) were diagnosed with primary breast cancer at the age of 50 years or older. A significant association between birth weight and breast cancer was found equivalent to an increase in risk of 9% per 1,000 g increase in birth weight (95% CI 2-17). The increase was observed for all age groups, representing both pre- and post-menopausal women, and irrespective of tumor characteristics. Adjustment for age at first birth and parity did not influence the results. Birth weight is positively associated with risk of breast cancer, indicating that prenatal factors are important in the etiology of breast cancer.     

Birth weight and mammographic density among postmenopausal women in Sweden

Birth weight is a significant predictor of breast cancer risk in adult life and mammary gland mass could be an intermediate stage in this long process. We have studied the association of birth size measurements with mammographic density, a marker of mammary gland mass. For a population‐based sample of 893 postmenopausal women without previous cancer in Sweden, we retrieved information on birth size from birth records and their most recent mammography. Film mammograms of the medio‐lateral oblique view were digitized and the Cumulus software was used for computer‐assisted semi‐automated thresholding of mammographic density. Results were analyzed using generalized linear models controlling for possible confounders. Mean percent mammographic density increased when comparing the extreme categories of birth weight (from 15.6% to 18.6%) and head circumference (from 15.5% to 20.4%), and the corresponding linear trends were statistically significant (p values 0.02 and 0.007, respectively). The associations were particularly strong when the cutoff for high versus low mammographic density was set at the relatively high value of 50%. Compared to women weighing 3001–3500 grams at birth, women with birth weights >4000g were at almost 3‐fold risk of developing high mammographic density (odds ratio: 2.9, 95% confidence interval 1.1 to 7.9). No association with mammographic density was evident with respect to birth length which, however, is known to be less accurately measured. These results indicate that adult breast density, a powerful predictor of breast cancer risk, has intrauterine roots, as reflected in birth size.     

Birth weight is associated with postmenopausal breast cancer risk in Swedish women

There is some evidence that birth weight is associated with breast cancer. Whether this association differs between premenopausal and postmenopausal ages is still unclear. The results from this study suggest that higher birth weight is a risk factor for postmenopausal breast cancer (OR 1.06, CI 1.00-1.12, per 100 g), independent of selected early-life and adult factors.     

Birth weight as a predictor of breast cancer: a case-control study in Norway

The hypothesis that birth weight is positively associated with adult risk of breast cancer implies that factors related to intrauterine growth may be important for the development of this malignancy. Using stored birth records from the two main hospitals in Trondheim and Bergen, Norway, we collected information on birth weight, birth length and placenta weight among 373 women who developed breast cancer. From the same archives, we selected as controls 1150 women of identical age as the cases without a history of breast cancer. Information on age at first birth and parity were collected from the Central Person Registry in Norway. Based on conditional logistic regression analysis, breast cancer risk was positively associated with birth weight and with birth length (P for trend=0.02). Birth weights in the highest quartile (3730 g or more) were associated with 40% higher risk (odds ratio, 1.4, 95% confidence interval, 1.1-1.9) of breast cancer compared to birth weights in the lowest quartile (less than 3090 g). For birth length, the odds ratio for women who were 51.5 cm or more (highest quartile) was 1.3 (95% confidence interval, 1.0-1.8) compared to being less than 50 cm (lowest quartile) at birth. Adjustment for age at first birth and parity did not change these estimates. Placenta weight was not associated with breast cancer risk. This study provides strong evidence that intrauterine factors may influence future risk of breast cancer. A common feature of such factors would be their ability to stimulate foetal growth and, simultaneously, to influence intrauterine development of the mammary gland.     

Birth weight and the risk of testicular cancer: a meta-analysis

The high incidence of testicular cancer in young males indicates a potential role of events during early life. Birth weight has been identified as a factor possibly associated with the risk of cancers later in life. To investigate the association between birth weight and testicular cancer, we conducted a Systematic Review and Meta-Analysis of published studies investigating the association between birth weight and testicular cancer. Data were combined using a fixed-effects model. Thirteen epidemiologic studies, published between 1983 and 2004, were included in the analysis, encompassing 5,663 patients with testicular cancer. Men weighing less than 2,500 grams at birth had a higher risk for developing testicular cancer later in life than those with normal birth weight (2,500-4,000 g) (OR = 1.18; 95% confidence interval (CI) 1.01-1.38). A similar trend was found for men with a birth weight above 4,000 g, (OR = 1.12; 95% CI 1.02-1.22). When seminoma and nonseminoma testicular cancer cases were considered separately, low birth weight was a risk factor specifically for seminomas (OR = 1.44; 95% CI 1.11-1.88). A U-shaped association was observed between birth weight and the risk for testicular cancer. The underlying biological mechanisms for this phenomenon remain to be elucidated.     

Gestational risk factors and childhood cancers: A cohort study in Taiwan

Gestational risk factors such as birth weight, gestational age and parity have been repeatedly found to be related to pediatric cancers, but few reports have emerged from Asian countries. Here we report on demographic and gestational factors in a Taiwanese cohort. Our study included all children born in Taiwan 2004–2014 for whom there was a birth record (n = 2,079,037), of which 1900 children had been diagnosed with cancer prior to age 12. We conducted multivariable hazard regression to examine associations between demographic and gestational factors with cancer. Greater parity (family with 2+ older children) was related to acute myeloid leukemia [Hazard ratio (HR) = 2.15, 95% confidence interval (CI): 1.31, 3.55), central nervous system tumors (HR = 1.67, CI: 1.13, 2.48) and neuroblastoma (HR = 1.67, CI: 1.07, 2.63). Hepatoblastoma cases had a higher risk of low birth weight (<2,500 g; HR = 3.01, CI: 1.85, 4.91), very preterm birth (<33 weeks gestation; HR = 13.71, CI: 7.45, 25.23), plural pregnancies (HR = 2.37, CI: 1.10, 5.14) and both small (HR = 2.13, CI: 1.23, 3.67) and large (HR = 1.83, CI: 1.01, 3.32) for gestational age. Germ cell tumors were more common among children born in rural areas (HR = 1.63, CI: 1.02, 2.60). Despite that Taiwan has lower rates of both high and low birthweight compared to other developed nations, we observed several similar associations to those reported in Western Countries. Further research should examine unique exposures in Taiwan that may be contributing to higher incidence of certain cancer types.     

Birth weight,weight over the adult life course and risk of breast cancer

Breast cancer has been suggested to potentially have prenatal origins. We examined associations between birth weight, body mass index (BMI) at four-time points over 25 years of adulthood, and risk of postmenopausal breast cancer, with emphasis on whether the association between birth weight and risk of breast cancer was mediated by weight and height changes over the adult life course. Postmenopausal women (n = 70,397) aged 50–79 years without breast cancer at enrollment (1993–1998) were followed up to 25 years. Weight and height were measured at baseline. Birth weight, and weights at ages 18, 35 and 50 were self-reported. Breast cancer cases were centrally adjudicated. Compared to women with birth weight of 6–8 pounds, women with birth weight of <6 pounds had lower risk of breast cancer (HR = 0.88 95% CI: 0.79–0.99). 44% and 21% of the relationship between birth weight and breast cancer risk was mediated by adult height and weight at baseline, respectively. Birth weight of 8 pounds or more was not associated with risk of postmenopausal breast cancer. Weight gain in adulthood was associated with increased risk of breast cancer regardless of time periods. In conclusion, lower birthweight was associated with lower risk of postmenopausal breast cancer, and this reduction in risk was significantly mediated by childhood or adolescent growth, especially by adult height. Our data suggest that reaching and maintaining a healthy weight during adulthood is key in the prevention of breast cancer.     

Birth outcome in women with breast cancer

We investigated whether maternal breast cancer affects birth outcome in a nationwide cohort study of 695 births from 1973 to 2002 of women with breast cancer with respect to preterm birth, low birth weight at term, stillbirth and congenital abnormalities as well as mean birth weight, compared with the outcomes of 33 443 births from unaffected mothers. There was no excess risk of adverse birth outcome for the 216 newborns of women with breast cancer before pregnancy. Stratification by mother's treatment did not change the results. For 37 newborns of women diagnosed during pregnancy, the prevalence ratio (PR) of preterm birth was 8.1 (95% confidence interval (CI): 3.8-17). However, 10 of the 12 preterm deliveries among these women were elective early deliveries. Among 442 births of women diagnosed in the 2 years from time of delivery, the PR of preterm birth was 1.4 (95% CI: 1.0-2.0), and the PR of low birth weight at term for boys was 2.9 (95% CI: 1.3-6.3). Overall, our results are reassuring regarding the risks of adverse birth outcome for breast cancer patients.     

上海市成人男女性身高与恶性肿瘤发病的前瞻性队列研究

目的:探讨上海市成人男女性身高与常见恶性肿瘤发生的相关性。方法:利用1996-2000年上海市女性健康队列(Shanghai women’s health study,SWHS)和2002—2006年上海市男性健康队列(Shanghai men’s health study,SMHS)基线调查资料获得身高和肿瘤相关信息,排除身高数据缺失和随访时间<1年的对象,最终女性队列74709人、男性队列61161人纳入本次数据分析对象。随访至2009年底,女性队列累积收集肿瘤病例4031例,男性队列累积收集肿瘤病例2047例。用COX回归模型估计身高与常见肿瘤的相对风险比(hazard ratio,HR)及其95%可信区间(95% confidence interval,95%CI)。结果:调整相关潜在混杂因子[如年龄、体重、体力活动、能量摄入、职业、经济收入和生理因素(仅对女性)等]后,身高每增加1个标准差单位(本研究中男、女性都为6cm),女性总肿瘤发生的HR值为1.04(95%CI:1.00～1.08),其中胃癌HR值为1.18(95%CI:1.05～1.33)、肾癌HR值为1.34(95%CI:1.06～1.70)、乳腺癌HR值为1.05(95%CI:0.99～1.12);男性总肿瘤发生的HR值为1.06(95%CI:1.00～1.11),其中肺癌HR值为1.11(95%CI:1.00～1.25)、胰腺癌HR值为1.34(95%CI:1.02～1.75)、直肠癌HR值为1.23(95%CI:1.01～1.49)、前列腺癌HR值为0.78(95%CI:0.66～0.94)。结论:身高与恶性肿瘤发病之间存在一定的联系,不同的肿瘤发生部位,其结果可能存在一定差异。     

Breast cancer: trends in international incidence in men and women

Background:

The age-standardised incidence of breast cancer varies geographically, with rates in the highest-risk countries more than five times those in the lowest-risk countries.

Methods:

We investigated the correlation between male (MBC) and female breast cancer (FBC) incidence stratified by female age-group (<50 years, and ⩾50 years) and used Poisson regression to examine male incidence rate ratios according to female incidence rates.

Results:

Age-adjusted breast cancer incidence rates for males and females share a similar geographic distribution (Spearman''s correlation=0.51; P<0.0001). A correlation with male incidence rates was found for the entire female population and for women aged 50 years and over. Breast cancer incidence rates in males aged <50 years were not associated with FBC incidence, whereas those in males aged ⩾50 years were. MBC incidence displays a small ‘hook'' similar to the Clemmesen''s hook for FBC, but at a later age than the female hook.

Interpretation:

Further investigation of possible explanations for these patterns is warranted. Although the incidence of breast cancer is much lower in men than in women, it may be possible to identify a cause common to both men and women.     

Birth size and subsequent risk for prostate cancer: a prospective population-based study in Norway

Studies on birth size characteristics and adult risk for prostate cancer have been few and inconclusive. We prospectively examined the association between birth size and risk for prostate cancer with particular emphasis on metastatic disease. A total of 19,681 singleton males born between 1920 and 1958, whose birth records were kept at St. Olav's University Hospital (Trondheim, Norway), were followed up for prostate cancer by linkage to the Norwegian Cancer Registry. A total of 159 cases of prostate cancer were diagnosed during follow-up; 33 had metastases at diagnosis. Overall, there was little evidence for any association between birth size and prostate cancer risk; however, there was a positive association for birth size and metastatic disease. Men in the highest quartile of birth length (> or =53 cm) had a relative risk of 2.5 (95% CI 1.0-6.3) compared to men in the lowest quartile (<51 cm). Further, men in the highest quartile of both birth weight and birth length had a relative risk of 3.8 (95% CI 1.2-12.0) for metastatic prostate cancer compared to men in the lowest category of both factors. These results support the hypothesis that factors that determine intrauterine growth could be important for aggressive forms of prostate cancer in adulthood.     

Cancer risk in Swedish women: the relation to size at birth

The relationship between fetal growth as indicated by weight and length at birth, and cancer risk in 1080 adult Swedish women was examined. Birth factors were retrieved from original midwife records for the years 1914, 1918, 1922 and 1930, and primary cancer cases were identified by matching with national and regional cancer registries through the year 1998. A positive and statistically significant increased risk for cancer was found with increasing birth weight or birth length for all site cancer and non-hormone related cancer, defined as all cancer sites excluding breast, uterus and ovary. Addition of factors suspected to influence cancer risk, maternal proteinuria, birth order, own parity and age at menarche, did not attenuate this relation. Previously only breast cancer has been reported to be related to size at birth in adult women and this is the first study to report that cancer sites other than the major hormone-related sites may be influenced by size at birth, as measured by either weight or length at birth; these findings warrant further investigation.     

Rice consumption and cancer incidence in US men and women

While both the 2012 and 2014 Consumer Reports concerned arsenic levels in US rice, no previous study has evaluated long‐term consumption of total rice, white rice and brown rice in relation to risk of developing cancers. We investigated this in the female Nurses' Health Study (1984–2010), and Nurses' Health Study II (1989–2009), and the male Health Professionals Follow‐up Study (1986–2008), which included a total of 45,231 men and 160,408 women, free of cancer at baseline. Validated food frequency questionnaires were used to measure rice consumption at baseline and repeated almost every 4 years thereafter. We employed Cox proportional hazards regression model to estimate multivariable relative risks (RRs) and 95% confidence intervals (95% CIs). During up to 26 years of follow‐up, we documented 31,655 incident cancer cases (10,833 in men and 20,822 in women). Age‐adjusted results were similar to multivariable‐adjusted results. Compared to participants with less than one serving per week, the multivariable RRs of overall cancer for individuals who ate at least five servings per week were 0.97 for total rice (95% CI: 0.85–1.07), 0.87 for white rice (95% CI: 0.75–1.01), and 1.17 for brown rice (95% CI: 0.90–1.26). Similar non‐significant associations were observed for specific sites of cancers including prostate, breast, colon and rectum, melanoma, bladder, kidney, and lung. Additionally, the null associations were observed among European Americans and non‐smokers, and were not modified by BMI. Long‐term consumption of total rice, white rice or brown rice was not associated with risk of developing cancer in US men and women.     

First pregnancy characteristics and subsequent breast cancer risk among young women

There is growing evidence that perinatal factors associated with altered gestational hormones may influence subsequent breast cancer risk in the mother. Events occurring during the first pregnancy may be particularly important. In this matched case-control study, we investigated the relation between characteristics of a woman's first pregnancy and her later breast cancer risk using linked records from the New York State birth and tumor registries. Cases were 2,522 women aged 22 to 55 diagnosed with breast cancer between 1978 and 1995 and who had also completed a first pregnancy in New York State (NY) at least 1 year prior to diagnosis. Controls were 10,052 primiparous women not diagnosed with breast or endometrial cancer in NY and matched to cases on county of residence and date of delivery. Information on factors characterizing the woman's first pregnancy was obtained from the pregnancy record of each subject. The association of these factors to breast cancer risk was assessed using conditional logistic regression. Extreme prematurity (< 32 weeks gestational age) was associated with elevated maternal breast cancer risk [adjusted odds ratio (OR)=2.1, 95% confidence interval (CI) 1.2,3.9], as were abruptio placentae (OR = 1.8, CI 1.1,3.0) and multifetal gestation (OR=1.8, CI 1.1,3.0). Preeclampsia was associated with a marked reduction in breast cancer risk among women who bore their first child after age 30 (OR=0.3, CI 0.2,0.7) and in the first 3 years after delivery (OR=0.2 (0.1-0.9). These findings suggest that certain perinatal factors influence maternal breast cancer risk and offer indirect support for a role of gestational hormones, and particularly gestational estrogens, in the etiology of breast cancer.     

Birth outcomes among offspring of adult cancer survivors: A population‐based study

Do cancer and cancer treatment influence patients' subsequent pregnancies and outcomes for the offspring? In this study, we compared birth outcomes in 3,915 female and male survivors and 144,653 controls from the general population with similar parity, by merging data from the Cancer Registry and the Medical Birth Registry of Norway. The cancer survivors were diagnosed at age 16–45 in the period 1967–2004. Subgroups of nulliparous survivors (childless before cancer) and primiparous (one pregnancy before and one after cancer) were analyzed, using logistic regression to compare birth outcomes with controls, focusing perinatal death, congenital anomalies, preterm birth (<37 gestational weeks) and low birth weight (LBW, <2,500 g). We adjusted for maternal age, birth period and educational level. Nulliparous female survivors' offspring had increased risk of preterm birth (OR = 1.30 [95% CI 1.05–1.61]) but similar risks of LBW and perinatal death as their controls. Primiparous female survivors differed from their controls, with higher frequency of preterm birth (OR = 1.89 [95% CI 1.40–2.56]) and LBW at term (OR = 2.02 [95% CI 1.15–3.55]). A borderline significant increase of perinatal death was seen among offspring of primiparous female survivors, with OR = 1.92 (95% CI 0.98–3.76). Offspring of male survivors did not differ from their controls. For all cancer types combined, no increased risk of congenital anomalies was seen among either female or male survivors' offspring. Pregnant female cancer survivors should be offered close follow‐up, as there is an increased risk of adverse birth outcomes, in particular among those with higher parities.     

Occupational magnetic field exposure and site-specific cancer incidence: a Swedish cohort study

Objective: Based on 1,596,959 men and 806,278 women, site-specific cancer incidence during 1971 through 1984 was analyzed in relation to occupational magnetic field exposure. The objective was to explore potential associations for cancer diseases beyond those extensively studied before (leukemia and brain tumors).Methods: Exposure was assessed from Census information on occupations that were linked to a job exposure matrix based on measurements. In a basic analysis, three levels of exposure were used. In addition, subjects with a more definite low exposure were compared with an aggregate of occupations with more definite exposures.Results: Observed associations were weak and there were no evident exposure–response relationships. For all cancer, an approximate 10% increase in risk was seen in the medium and high exposure groups. Several types of cancer were associated with exposure among men, including cancer of the colon, biliary passages and liver, larynx and lung, testis, kidney, urinary organs, malignant melanoma, non-melanoma skin cancer, astrocytoma III–IV. For women, associations were seen for cancer of the lung, breast, corpus uteri, malignant melanoma and chronic lymphocytic leukemia.Conclusions: In the analysis of occupations with a more definite exposure, the most notable finding for men was an increased risk of testicular cancer in young workers, and for women a clear association emerged for cancer of the corpus uteri. The outcome suggests an interaction with the endocrine/immune system.     

Birth weight and risk of cancer

BACKGROUND: It is well established that prenatal biologic processes are important for the development of some childhood cancers, whereas less is known regarding their influence on adult cancer risk. High birth weight has been associated with risk of breast cancer, whereas studies of other specific cancers and all cancers together have been less conclusive. METHODS: The authors established a cohort of more than 200,000 men and women who were born between 1936 and 1975. Birth weights were obtained from school health records and information concerning cancer from the Danish Cancer Registry. Follow-up was performed between April 1, 1968 and December 31, 2003. During 6,975,553 person-years of follow-up, a total of 12,540 primary invasive cancers were diagnosed. RESULTS: Analyses of site-specific cancers revealed that the majority of cancers had a positive linear association with birth weight. Departures from a positive linear association were found to be statistically significant for cancers of the pancreas and bladder, which demonstrated a V-shaped association, and testicular cancer, which demonstrated an inverse association with birth weight. Excluding these 3 exceptions, the trends for the individual cancer sites were not heterogeneous, and the overall trend was a relative risk of 1.07 (95% confidence interval, 1.03-1.11) per 1000-g increase in birth weight. This trend was the same in men and women and in all age groups. CONCLUSIONS: A 7% increase in cancer risk was observed per 1000-g increase in birth weight. Few cancers demonstrated a nonlinear association with birth weight, and testicular cancer was found to be negatively associated with birth weight. The authors hypothesized that the biologic explanation behind the association between birth weight and cancer at different sites should be sought in a common pathway.     

Lung cancer rates convergence in young men and women in the United States: analysis by birth cohort and histologic type

Age-specific rates of lung cancer have been consistently higher for men than for women in the United States, due primarily to different patterns of cigarette smoking. Gender differences in cigarette smoking have diminished in recent birth cohorts, however, especially among whites. We used U.S. population-based incidence and mortality data and examined trends in age-specific rates of lung cancer by birth cohort according to gender, ethnic group, and histology to evaluate the generational changes in U.S. lung cancer risk for men vs. women. All tests of statistical significance are 2-sided (95% confidence interval [CI]). Lung cancer mortality rates have converged between men and women born after 1960, especially in whites. The male-to-female (M:F) mortality rate ratio for ages 35-39 years decreased from 3.0 (95% CI = 2.7-3.4) around the 1915 birth cohort to 1.1 (95% CI = 1.0-1.1) around the 1960 birth cohort among whites and from 4.0 (95% CI = 3.2-5.0) around the 1925 birth cohort to 1.5 (95% CI = 1.3-1.7) around the 1960 birth cohort among blacks. Similarly, incidence rates for white men and women converged rapidly for adenocarcinoma, small cell carcinoma, and large cell carcinoma, but less so for squamous cell carcinoma. These findings reflect the smoking patterns among white and black men and women: cigarette smoking prevalence at age 24 was essentially equal among white men and women born after 1960 but continued to be higher in black men than women. The convergence of lung cancer death rates among men and women born after 1960s supports the idea that males and females maybe equally susceptible to develop lung cancer from a given amount of cigarette smoking, rather than the hypothesis that women are more susceptible.