Growth patterns and the risk of breast cancer in women

Perinatal and childhood factors and risk of breast cancer subtypes in adulthood

BACKGROUND

Accumulated exposure to hormones and growth factors during early life may influence the future risk of breast cancer (BC). This study examines the influence of childhood-related, socio-demographic and anthropometric variables on BC risk, overall and by specific pathologic subtypes.

METHODS

This is a case-control study where 1539 histologically-confirmed BC cases (23-85 years) and 1621 population controls, frequency matched by age, were recruited in 10 Spanish provinces. Perinatal and childhood-related characteristics were directly surveyed by trained staff. The association with BC risk, globally and according to menopausal status and pathologic subtypes, was evaluated using logistic and multinomial regression models, adjusting for tumor specific risk factors.

RESULTS

Birth characteristics were not related with BC risk. However, women with high socioeconomic level at birth presented a decreased BC risk (OR=0.45; 95% CI=0.29-0.70), while those whose mothers were aged over 39 years at their birth showed an almost significant excess risk of hormone receptor positive tumors (HR+) (OR=1.35; 95% CI=0.99-1.84). Women who were taller than their girl mates before puberty showed increased postmenopausal BC risk (OR=1.26; 95% CI=1.03-1.54) and increased HR+ BC risk (OR=1.26; 95% CI=1.04-1.52). Regarding prepubertal weight, while those women who were thinner than average showed higher postmenopausal BC risk (OR=1.46; 95% CI=1.20-1.78), associated with HR+ tumors (OR=1.34; 95% CI=1.12-1.61) and with triple negative tumors (OR=1.56; 95% CI=1.03-2.35), those who were heavier than average presented lower premenopausal BC risk (OR=0.64; 95% CI=0.46-0.90) and lower risk of epidermal growth factor receptor positive tumors (OR=0.61; 95% CI=0.40-0.93).

CONCLUSION

These data reflect the importance of hormones and growth factors in the early stages of life, when the mammary gland is in development and therefore more vulnerable to proliferative stimuli.

Height and Breast Cancer Risk: Evidence From Prospective Studies and Mendelian Randomization

BACKGROUND

Epidemiological studies have linked adult height with breast cancer risk in women. However, the magnitude of the association, particularly by subtypes of breast cancer, has not been established. Furthermore, the mechanisms of the association remain unclear.

METHODS

We performed a meta-analysis to investigate associations between height and breast cancer risk using data from 159 prospective cohorts totaling 5216302 women, including 113178 events. In a consortium with individual-level data from 46325 case patients and 42482 control patients, we conducted a Mendelian randomization analysis using a genetic score that comprised 168 height-associated variants as an instrument. This association was further evaluated in a second consortium using summary statistics data from 16003 case patients and 41335 control patients.

RESULTS

The pooled relative risk of breast cancer was 1.17 (95% confidence interval [CI] = 1.15 to 1.19) per 10cm increase in height in the meta-analysis of prospective studies. In Mendelian randomization analysis, the odds ratio of breast cancer per 10cm increase in genetically predicted height was 1.22 (95% CI = 1.13 to 1.32) in the first consortium and 1.21 (95% CI = 1.05 to 1.39) in the second consortium. The association was found in both premenopausal and postmenopausal women but restricted to hormone receptor-positive breast cancer. Analyses of height-associated variants identified eight new loci associated with breast cancer risk after adjusting for multiple comparisons, including three loci at 1q21.2, DNAJC27, and CCDC91 at genome-wide significance level P < 5×10(-8).

CONCLUSIONS

Our study provides strong evidence that adult height is a risk factor for breast cancer in women and certain genetic factors and biological pathways affecting adult height have an important role in the etiology of breast cancer.

The interaction between early-life body size and physical activity on risk of breast cancer

While early-life body leanness is associated with increased breast cancer risk, early-life physical activity may protect against breast cancer. We examined whether the excess risk among lean girls is modified by their levels of prior, concurrent, or future physical activity. We conducted an analysis among 74,723 women in the Nurses' Health Study II (follow-up 1997-2011). Participants recalled their body size at ages 5, 10 and 20 years in 1989 using a 9-level pictogram (Level 1 most lean). In 1997, they reported adolescent levels of physical activity (ages 12-13 and 14-17 years). Cox proportional hazards models estimated the overall association of body size with breast cancer risk and assessed interactions of adolescent physical activity with body size at three different age periods (5-10, 10-20 and 20 years), adjusting for early-life and adult risk factors for breast cancer. Regardless of levels of adolescent physical activity, early-life body leanness (level 1-2 vs. 4.5+) was significantly associated with higher breast cancer risk. The association was slightly attenuated among those who were active (60+ MET-hr/wk) during adolescence compared to those who were inactive (<30 MET-hr/wk) (body size at ages 5-10 years: hazard ratio = 1.37, 95% confidence interval = 1.04-1.81 vs. 1.66, 1.29-2.12), but the interaction was not significant (p = 0.72). The results were similar for body size at three different age periods. Being lean during early life is a risk factor for breast cancer among both inactive and active girls. Adolescent physical activity did not significantly modify the association, although some interaction cannot be excluded.

Preventing breast cancer now by acting on what we already know

The age-specific rate of breast cancer rises rapidly through premenopausal years and significantly more slowly after menopause. Reproductive factors affect cell proliferation and the accumulation of genetic changes. Lifetime risk of breast cancer is linearly related to the length of the interval from menarche to first birth. Lifestyle changes that accompany industrialization, together with shifting reproductive patterns, drive up incidence rates. Prevention must begin early in the life as almost one-quarter of cases are diagnosed before age 50 in high-income countries. This requires greater emphasis on prevention across the life course to address the global burden of breast cancer.

Body fatness during childhood and adolescence and breast density in young women: a prospective analysis

INTRODUCTION

Overweight and obesity in childhood and adolescence are associated with reduced breast cancer risk, independent of adult body mass index (BMI). These associations may be mediated through breast density.

METHODS

We prospectively examined associations of early life body fatness with adult breast density measured by MRI in 182 women in the Dietary Intervention Study in Children (DISC) who were ages 25-29 at follow-up. Height, weight, and other factors were measured at baseline (ages 8-10) and annual clinic visits through adolescence. We used linear mixed-effects models to quantify associations of percent breast density and dense and non-dense breast volume at ages 25-29 with quartiles of age-specific youth body mass index (BMI) Z-scores, adjusting for clinic, treatment group, current adult BMI, and other well-established risk factors for breast cancer and predictors of breast density.

RESULTS

We observed inverse associations between age-specific BMI Z-scores at all youth clinic visits and percent breast density, adjusting for current adult BMI and other covariates (all p values <0.01). Women whose baseline BMI Z-scores (at ages 8-10 years) were in the top quartile had significantly lower adult breast density, after adjusting for current adult BMI and other covariates [least squares mean (LSM): 23.4 %; 95 % confidence interval (CI): 18.0 %, 28.8 %] compared to those in the bottom quartile (LSM: 31.8 %; 95 % CI: 25.2 %, 38.4 %) (p trend <0.01). Significant inverse associations were also observed for absolute dense breast volume (all p values <0.01), whereas there were no clear associations with non-dense breast volume.

CONCLUSIONS

These results support the hypothesis that body fatness during childhood and adolescence may play an important role in premenopausal breast density, independent of current BMI, and further suggest direct or indirect influences on absolute dense breast volume.

CLINICAL TRIALS REGISTRATION NUMBER

NCT00458588 ; April 9, 2007.

Does salt have a permissive role in the induction of puberty?

Puberty is starting earlier than ever before and there are serious physiological and sociological implications as a result of this development. Current research has focused on the potential role of high caloric, and commensurate high adiposity, contributions to early puberty. However, girls with normal BMI also appear to be initiating puberty earlier. Westernized diets, in addition to being high in fat and sugar, are also high in salt. To date, no research has investigated a link between elevated salt and the reproductive axis. We hypothesize that a high salt diet can result in an earlier onset of puberty through three mechanisms that are not mutually exclusive. (1) High salt activates neurokinin B, a hormone that is involved in both the reproductive axis and salt regulation, and this induces kisspeptin release and ultimate activation of the reproductive axis. (2) Vasopressin released in response to high salt acts on vasopressin receptors expressed on kisspeptin neurons in the anteroventral periventricular nucleus, thereby stimulating gonadotropin releasing hormone and subsequently luteinizing hormone secretion. (3) Salt induces metabolic changes that affect the reproductive axis. Specifically, salt acts indirectly to modulate adiposity, ties in with the obesity epidemic, and further compounds the pathologic effects of obesity. Our overall hypothesis offers an additional cause behind the induction of puberty and provides testable postulates to determine the mechanism of potential salt-mediated affects on puberty.

Anthropometric Measures at Multiple Times Throughout Life and Prostate Cancer Diagnosis, Metastasis, and Death

BACKGROUND

Previous studies of prostate cancer (PCa) risk and anthropometrics (ie, body measurements) were based on single measurements or obtained over limited time spans.

OBJECTIVE

To study the association between anthropometrics measured at multiple time points in life and their relation to later diagnosis, metastasis, or death from PCa.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study includes 27 167 Swedish men enrolled in two population-based projects from 1974 to 1996. PCa diagnosis up to December 31, 2006, disease information, gestation time, and anthropometrics at birth, military conscript testing, and adulthood were collected. A total of 1355 PCa cases were matched with 5271 controls.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariate conditional logistic regression was used to determine whether clinical diagnosis, metastasis, or PCa death was associated with low birth weight (weight <2500 g); with small size for gestational age; or with weight, length, or body mass index (BMI) at birth, adolescence (aged 16-22 yr), or early middle age (aged 44-50 yr).

RESULTS AND LIMITATIONS

Apart from weight at adolescence, which was associated with an increased risk of PCa diagnosis (odds ratio [OR] per 5 kg: 1.05; 95% confidence interval [CI], 1.01-1.09; p=0.026), preadulthood measurements were not associated with any PCa end point. Adulthood parameters were not associated with diagnosis. In contrast, weight and BMI at early middle age were significantly associated with metastasis (OR per 5 kg: 1.13; 95% CI, 1.06-1.20; p<0.0001, and OR: 1.09; 95% CI, 1.05-1.14; p<0.0001) and death (OR per 5 kg: 1.11 (95% CI, 1.03-1.19; p=0.005, and OR: 1.08; 95% CI, 1.03-1.13; p=0.003), respectively. It remains unclear whether these results apply to men of nonwhite origin, to populations with active PCa screening programs, or to countries without socialized health care.

CONCLUSIONS

The analyses of these large data sets demonstrate that significant effects of body characteristics (with links to metabolic syndrome) measured at early middle age are associated with PCa disease severity, metastatic progression, and outcome. Conversely, measurements at birth and adolescence are not associated with PCa prevalence or outcome.

PATIENT SUMMARY

Increased weight and body mass index in adults is associated with a higher risk of prostate cancer metastasis and death.

Puberty and perimenopause: reproductive transitions and their implications for women's health

This scoping review synthesizes existing research on two major transitions in females' lives: puberty and perimenopause. These two periods of vast physiological change demarcate the beginning and the end of the reproductive life cycle and are associated with major neuroendocrine reorganization across two key systems, the hypothalamic-pituitary-gonadal (HPG) axis the hypothalamus-pituitary-adrenal (HPA) axis. Despite growing evidence suggesting that the timing and experience of puberty and perimenopause are related to various physical and mental health outcomes (e.g., mood disorders, metabolism, cardiovascular health, autoimmune conditions, and cancer), these two processes are rarely examined together. In this paper, we bridge these disparate literatures to highlight similarities, isolate inconsistencies, and identify important areas for future research in women's health.

Early life body mass trajectories and mortality in older age: findings from the Helsinki Birth Cohort Study

BACKGROUND

Overweight and obesity in childhood have been linked to an increased risk of adult mortality, but evidence is still scarce.

METHODS

We identified trajectories of body mass index (BMI) development in early life and investigated their mortality risk. Data come from the Helsinki Birth Cohort Study, in which 4943 individuals, born 1934-1944, had serial measures of weight and height from birth to 11 years extracted from health care records, weight and height data in adulthood, and register-based mortality data for 2000-2010.

RESULTS

Three early BMI trajectories (increasing, average, and average-to-low for men and increasing, average, and low-to-high BMI for women) were identified. Women with an increasing or low-to-high BMI (BMI lower in early childhood, later exceeded average) trajectory had an increased risk of all-cause mortality compared to those with an average BMI trajectory (HR 1.55, 95% CI 1.07-2.23; and HR 1.57, 95% CI 1.04-2.37, respectively). Similar associations were observed for cancer mortality. Among men, BMI trajectories were not associated with all-cause mortality, but those with average-to-low BMI (BMI first similar then dropped below average) had an increased risk of cancer mortality.

CONCLUSIONS

An increasing BMI in early life may shorten the lifespan of maturing cohorts as they age, particularly among women.

Body mass index at early adulthood, subsequent weight change and cancer incidence and mortality

Obesity later in adulthood is associated with increased risks of many cancers. However, the effect of body fatness in early adulthood, and change in weight from early to later adulthood on cancer risk later in life is less clear. We used data from 13,901 people aged 45-64 in the Atherosclerosis Risk in Communities cohort who at baseline (1987-1989) self-reported their weight at the age of 25 and had weight and height measured. Incident cancers were identified through 2006 and cancer deaths were ascertained through 2009. Multivariable Cox proportional hazard models were used to relate body mass index (BMI) at age 25 and percent weight change from age 25 to baseline to cancer incidence and mortality. After adjusting for weight change from age 25 until baseline, a 5 kg/m(2) increment in BMI at age 25 was associated with a greater risk of incidence of all cancers in women [hazard ratio (95% confidence interval): 1.10 (1.02-1.20)], but not in men. Associations with incident endometrial cancer were strong [1.83 (1.47-2.26)]. After adjusting for BMI at age 25, a 5% increment in weight from age 25 to baseline was associated with a greater risk of incident postmenopausal breast cancer [1.05 (1.02-1.07)] and endometrial cancer [1.09 (1.04-1.14)] in women and incident colorectal cancer [1.05 (1.00-1.10)] in men. Excess weight during young adulthood and weight gain from young to older adulthood may be independently associated with subsequent cancer risk. Excess weight and weight gain in early adulthood should be avoided.

A conceptual framework for the developmental origins of health and disease

In the last decades, the developmental origins of health and disease (DOHaD) have emerged as a vigorous field combining experimental, clinical, epidemiological and public health research. Its goal is to understand how events in early life shape later morbidity risk, especially of non-communicable chronic diseases. As these diseases become the major cause of morbidity and mortality worldwide, research arising from DOHaD is likely to gain significance to public health and economic development. But action may be hindered by the lack of a firm mechanistic explanation and of a conceptual basis, especially regarding the evolutionary significance of the DOHaD phenomenon. In this article, we provide a succinct historical review of the research into the relationship between development and later disease, consider the evolutionary and developmental significance and discuss the underlying mechanisms of the DOHaD phenomenon. DOHaD should be viewed as a part of a broader biological mechanism of plasticity by which organisms, in response to cues such as nutrition or hormones, adapt their phenotype to environment. These responses may be divided into those for immediate benefit and those aimed at prediction of a future environment: disease occurs in the mismatch between predicted and realized future. The likely mechanisms that enable plasticity involve epigenetic processes, affecting the expression of genes associated with regulatory pathways. There is now evidence that epigenetic marks may be inherited and so contribute to non-genomic heritable disease risk. We end by discussing the global significance of the DOHaD phenomenon and its potential applications for public health purposes.

Facing the noncommunicable disease (NCD) global epidemic--the battle of prevention starts in utero--the FIGO challenge

Noncommunicable diseases (NCDs) are responsible for 36 million deaths every year. Of this death toll, nearly 80% (29 million) occur in low- and median-income countries. More than 9 million deaths attributed to NCDs occur in people under 60 years of age. National economies are suffering considerable losses due to premature death or disability to work resulting from heart disease, stroke, and diabetes. The knowledge that in utero and in early childhood certain processes can affect the risk of developing NCDs provides an opportunity to enforce interventions during this critical time, when they may have the greatest effect. Using appropriate protocols, the health-care provider can educate mothers about the risks of certain nutritional and environmental exposures and integrate health promotion on the agenda, as part of the social and economic development. All this could motivate a substantial reduction in the risk of NCDs. Current and future health challenges demand new and changing competencies that should form the basis for education, training, and workforce planning. The International Federation of Gynaecology and Obstetrics (FIGO) is aware of that responsibility and has joined hands with other agencies and organizations that make a considerable effort in providing appropriate prenatal care programs to prevent and treat most of the common preconditioning factors, especially in low-income countries.

Adolescent physical activity and inactivity: a prospective study of risk of benign breast disease in young women

In previous investigations of adolescent activity recalled in adulthood, modest reductions in risk of benign breast disease (BBD) and premenopausal breast cancer were seen with moderate-strenuous activity during high school. We therefore investigated physical activity, walking, and recreational inactivity (watching TV-videos, playing computer-videogames) reported by adolescent girls in relation to their subsequent risk for BBD as young women. The Growing Up Today Study includes 9,039 females, 9-15 years at study initiation (1996), who completed questionnaires annually through 2001, then in 2003, 2005, 2007, 2010 and 2013. Annual surveys (1996-2001) obtained data on physical and sedentary activities during the past year. Beginning in 2005, women (≥18 years) reported whether they had ever been diagnosed with BBD confirmed by breast biopsy (n = 133 cases, to 11/01/2013). Logistic regression (adjusted for baseline adiposity and age; additional factors in multivariable-adjusted models) estimated associations between adolescent activities (moderate-vigorous, walking, METS, inactivity) and biopsy-confirmed BBD in young women. Girls who walked the most had significantly lower risk of BBD (multivariable-adjusted OR = 0.61, ≥30 vs ≤15 min/day; p = .049). We observed no evidence that inactivity (≥3 vs <2 h/day OR = 1.02, p = .92) or METS (top vs bottom tertile OR = 1.19, p = .42) were associated with BBD. Accounting for factors including family history, childhood adiposity, and other activities and inactivities, adolescent girls who walked the most were at lower risk for BBD. We found no evidence that high moderate-vigorous activity might reduce risk, nor did we observe any association with inactivity. Continued follow-up will re-evaluate these findings as more BBD cases, and ultimately breast cancer, are diagnosed.

Prevalence of risk factors for breast cancer in German airline cabin crew: a cross-sectional study

BACKGROUND

Many epidemiological studies point to an increased risk of breast cancer among female airline cabin crew. Possible causes include occupational factors (e.g. cosmic radiation exposure, chronodisruption), as well as lifestyle and reproductive factors.

AIMS

To investigate the frequency of various risk factors in German flight attendants which are recognised to be associated with breast cancer.

METHODS

2708 current and former female cabin crew were randomly selected by a flight attendants' union and mailed a questionnaire; 1311 responded (48% response). Descriptive statistics were used to compare the distribution of breast cancer risk factors with general German population data.

RESULTS

On average, cabin crew were 3.0 cm (95% CI 2.7-3.3) taller than the comparison group, while their body mass index was 2.5 kg/m(2) (95% CI 2.4-2.6) lower. We found less use of hormone replacement therapy, but longer average use of oral contraceptives. Nulliparity among respondents aged 45+ was 57% (95% CI 54%-60%) compared to 16%. Average age at first birth was 32.1 years (95% CI 31.7-32.4) vs. 25.5 years. The birth rate was 0.62 (95% CI 0.58-0.67), less than half the population average of 1.34. Alcohol consumption was considerably higher, whereas cabin crew tended to smoke less and performed more physical exercise.

CONCLUSION

We found important differences in terms of anthropometric, gynaecological, reproductive and lifestyle factors. Some of these differences (e.g. higher nulliparity, alcohol consumption, taller size) could contribute to a higher breast cancer risk, whereas others could lead to a reduction (e.g. increased physical exercise, lower BMI, less HRT use).

Body size across the life course and risk of premenopausal and postmenopausal breast cancer in Black women, the Carolina Breast Cancer Study, 1993-2001

BACKGROUND

It is believed that greater adiposity is associated with reduced risk of breast cancer in premenopausal but increased risk in postmenopausal women. However, few studies have evaluated these relationships among Black women or examined anthropometric measures other than near-diagnosis body mass index (BMI).

PURPOSE

This study investigated associations between measures of body size across the life course and breast cancer risk among Black and White women living in the US South.

METHODS

We used data from the Carolina Breast Cancer Study, a population-based case-control study of invasive breast cancer in North Carolina women aged 20-74 years. We assessed nine body size variables, including age 10 relative weight; age 18 BMI; adult weight gain; "reference" BMI 1 year before interview; and post-diagnosis measured BMI and abdominal obesity measures.

RESULTS

Among premenopausal Whites, heavier childhood relative weight was associated with decreased cancer risk [odds ratio (OR) 0.48 95 % confidence interval 0.33-0.70]. Among premenopausal Blacks, greater adult waist circumference and waist-to-hip ratio (WHR) were associated with increased risk [waist OR 1.40 (1.00-1.97) and high tertile WHR OR 2.03 (1.29-3.19)], with associations for WHR in a similar direction in Whites. Among postmenopausal women, recalled body size was not associated with risk, except for increased risk associated with adult weight gain among White non-hormone therapy users. ER/PR status and hormone therapy use also modified other associations.

DISCUSSION

In this population, greater adult BMI was not associated with increased breast cancer risk, but some measures of early-life body size and abdominal obesity were associated with risk.

Growth hormone is secreted by normal breast epithelium upon progesterone stimulation and increases proliferation of stem/progenitor cells

Using in vitro and in vivo experimental systems and in situ analysis, we show that growth hormone (GH) is secreted locally by normal human mammary epithelial cells upon progesterone stimulation. GH increases proliferation of a subset of cells that express growth hormone receptor (GHR) and have functional properties of stem and early progenitor cells. In 72% of ductal carcinoma in situ lesions, an expansion of the cell population that expresses GHR was observed, suggesting that GH signaling may contribute to breast cancer development.

Season of birth and other perinatal risk factors for melanoma

BACKGROUND

Ultraviolet radiation (UVR) exposure is the main risk factor for cutaneous malignant melanoma (CMM), but its specific effect in infancy is unknown. We examined whether season of birth, a proxy for solar UVR exposure in the first few months of life, is associated with CMM in childhood through young adulthood.

METHODS

National cohort study of 3,571,574 persons born in Sweden in 1973-2008, followed up for CMM incidence through 2009 (maximum age 37 years) to examine season of birth and other perinatal factors.

RESULTS

There were 1595 CMM cases in 63.9 million person-years of follow-up. We found a sinusoidal pattern in CMM risk by season of birth (P=0.006), with peak risk corresponding to birthdates in spring (March-May). Adjusted odds ratios for CMM by season of birth were 1.21 [95% confidence interval (CI), 1.05-1.39; P=0.008] for spring, 1.07 (95% CI, 0.92-1.24; P=0.40) for summer and 1.12 (95% CI, 0.96-1.29; P=0.14) for winter, relative to fall. Spring birth was associated with superficial spreading subtype of CMM (P=0.02), whereas there was no seasonal association with nodular subtype (P=0.26). Other CMM risk factors included family history of CMM in a sibling (>6-fold) or parent (>3-fold), female gender, high fetal growth and high paternal education level.

CONCLUSIONS

In this large cohort study, persons born in spring had increased risk of CMM in childhood through young adulthood, suggesting that the first few months of life may be a critical period of UVR susceptibility. Sun avoidance in early infancy may play an important role in the prevention of CMM in high-risk populations.

Childhood body mass index and the risk of prostate cancer in adult men

BACKGROUND

Prostate cancer aetiology is poorly understood. It may have origins early in life; previously we found a positive association with childhood height. The effects of early life body mass index (BMI; kg m(-2)) on prostate cancer remain equivocal. We investigated if childhood BMI, independently and adjusted for height, is positively associated with adult prostate cancer.

METHODS

Subjects were a cohort of 125208 boys formed from the Copenhagen School Health Records Register, born 1930-1969 with height and weight measurements at 7-13 years. Cases were identified through linkage to the Danish Cancer Registry. Cox proportional hazards regressions were performed.

RESULTS

Overall, 3355 men were diagnosed with prostate cancer. Body mass index during childhood was positively associated with adult prostate cancer. The hazard ratio of prostate cancer was 1.06 (95% confidence interval (CI): 1.01-1.10) per BMI z-score at age 7, and 1.05 (95% CI: 1.01-1.10) per BMI z-score at age 13. Estimates were similar and significant at all other ages. However, adjustment for childhood height attenuated the associations at all but the youngest ages as most estimates became nonsignificant.

CONCLUSIONS

These results suggest that at most childhood ages, BMI does not confer an additional risk for prostate cancer beyond that of height.

Breast cancer risk accumulation starts early: prevention must also

Nearly one in four breast cancers is diagnosed before the age of 50, and many early-stage premalignant lesions are present but not yet diagnosed. Therefore, we review evidence to support the strategy that breast cancer prevention efforts must begin early in life. This study follows the literature review methods and format. Exposures during childhood and adolescence affect a woman's long-term risk of breast cancer, but have received far less research attention than exposures that occur later in life. Breast tissue undergoes rapid cellular proliferation between menarche and first full-term pregnancy, and risk accumulates rapidly until the terminal differentiation that accompanies first pregnancy. Evidence on childhood diet and growth in height, and adolescent alcohol intake, among other adolescent factors is related to breast cancer risk and risk of premalignant proliferative benign lesions. Breast cancer prevention efforts will have the greatest effect when initiated at an early age and continued over a lifetime. Gaps in knowledge are identified and deserve increase attention to inform prevention.

Effect of milk proteins on linear growth and IGF variables in overweight adolescents

OBJECTIVE

Milk may stimulate growth acting via insulin-like growth factor-I (IGF-I) secretion but the effect in adolescents is less examined. This study investigates the effect of milk proteins on linear growth, IGF-I, IGF binding protein-3 (IGFBP-3) and IGF-I/IGFBP-3 ratio in overweight adolescents.

DESIGN

The trial included 193 overweight adolescents aged 12-15 years. They were randomized to drink 1L/day of: skimmed milk, whey, casein or water for 12 weeks; all milk-based drinks contained 35 g protein/L. A subgroup of 32 adolescents was examined 12 weeks before they were randomized into the groups and started the intervention (pre-test control group). Examinations included anthropometry, diet registration and blood samples which were analyzed for IGF-I and IGFBP-3 by chemiluminescence methods. The effects of milk-based drinks on linear growth, IGF-I, IGFBP-3 and IGF-I availability, calculated as the IGF-I/IGFBP-3 ratio, were compared with baseline, the pre-test control group and water.

RESULTS

IGF-I increased with skimmed milk (P=0.015) and tended to increase with casein (P=0.075) compared to the pre-test control group. IGFBP-3 but not IGF-I increased with skimmed milk (P=0.006) and casein (P=0.001) compared to water. There was no difference in height or height Z-score for any of the milk-based test drink groups compared to water or compared to the pre-test control group. However, height Z-score decreased within the whey group.

CONCLUSIONS

Skimmed milk and casein may have a stimulating effect on the IGF-I system whereas there was no positive effect on height in overweight adolescents during this 12 week intervention.

Timing of pubertal stages and breast cancer risk: the Breakthrough Generations Study

INTRODUCTION

Breast development and hormonal changes at puberty might affect breast cancer risk, but epidemiological analyses have focussed largely on age at menarche and not at other pubertal stages.

METHODS

We investigated associations between the timing of pubertal stages and breast cancer risk using data from a cohort study of 104,931 women (Breakthrough Generations Study, UK, 2003-2013). Pubertal variables were reported retrospectively at baseline. Breast cancer risk was analysed using Cox regression models with breast cancer diagnosis as the outcome of interest, attained age as the underlying time variable, and adjustment for potentially confounding variables.

RESULTS

During follow-up (mean = 4.1 years), 1094 breast cancers (including ductal carcinoma in situ) occurred. An increased breast cancer risk was associated with earlier thelarche (age when breast growth begins; HR [95% CI] = 1.23 [1.02, 1.48], 1 [referent] and 0.80 [0.69, 0.93] for ≤10, 11-12 and ≥13 years respectively), menarche (initiation of menses; 1.06 [0.93, 1.21], 1 [referent] and 0.78 [0.62, 0.99] for ≤12, 13-14 and ≥15 years), regular periods (0.99 [0.83, 1.18], 1 [referent] and 0.74 [0.59, 0.92] for ≤12, 13-14 and ≥15 years) and age reached adult height (1.25 [1.03, 1.52], 1 [referent] and 1.07 [0.87, 1.32] for ≤14, 15-16 and ≥17 years), and with increased time between thelarche and menarche (0.87 [0.65, 1.15], 1 [referent], 1.14 [0.96, 1.34] and 1.27 [1.04, 1.55] for <0, 0, 1 and ≥2 years), and shorter time between menarche and regular periods (1 [referent], 0.87 [0.73, 1.04] and 0.66 [0.50, 0.88] for 0, 1 and ≥2 years). These associations were generally similar when considered separately for premenopausal and postmenopausal breast cancer.

CONCLUSIONS

Breast duct development may be a time of heightened susceptibility to risk of carcinogenesis, and greater attention needs to be given to the relation of breast cancer risk to the different stages of puberty.

Birth weight, childhood body mass index, and height in relation to mammographic density and breast cancer: a register-based cohort study

Introduction

High breast density, a strong predictor of breast cancer may be determined early in life. Childhood anthropometric factors have been related to breast cancer and breast density, but rarely simultaneously. We examined whether mammographic density (MD) mediates an association of birth weight, childhood body mass index (BMI), and height with the risk of breast cancer.

Methods

13,572 women (50 to 69 years) in the Copenhagen mammography screening program (1991 through 2001) with childhood anthropometric measurements in the Copenhagen School Health Records Register were followed for breast cancer until 2010. With logistic and Cox regression models, we investigated associations among birth weight, height, and BMI at ages 7 to 13 years with MD (mixed/dense or fatty) and breast cancer, respectively.

Results

8,194 (60.4%) women had mixed/dense breasts, and 716 (5.3%) developed breast cancer. Childhood BMI was significantly inversely related to having mixed/dense breasts at all ages, with odds ratios (95% confidence intervals) ranging from 0.69 (0.66 to 0.72) at age 7 to 0.56 (0.53 to 0.58) at age 13, per one-unit increase in z-score. No statistically significant associations were detected between birth weight and MD, height and MD, or birth weight and breast cancer risk. BMI was inversely associated with breast cancer, with hazard ratios of 0.91 (0.83 to 0.99) at age 7 and 0.92 (0.84 to 1.00) at age 13, whereas height was positively associated with breast cancer risk (age 7, 1.06 (0.98 to 1.14) and age 13, 1.08 (1.00 to 1.16)). After additional adjustment for MD, associations of BMI with breast cancer diminished (age 7, 0.97 (0.88 to 1.06) and age 13, 1.01 (0.93 to 1.11)), but remained with height (age 7, 1.06 (0.99 to 1.15) and age 13, 1.09 (1.01 to 1.17)).

Conclusions

Among women 50 years and older, childhood body fatness was inversely associated with the breast cancer risk, possibly via a mechanism mediated by MD, at least partially. Childhood tallness was positively associated with breast cancer risk, seemingly via a pathway independent of MD. Birth weight was not associated with MD or breast cancer in this age group.

Epithelial cancers in the post-genomic era: should we reconsider our lifestyle?

The age-related epithelial cancers of the breast, colorectum and prostate are the most prevalent and are increasing in our aging populations. Epithelial cells turnover rapidly and mutations naturally accumulate throughout life. Most epithelial cancers arise from this normal mutation rate. All elderly individuals will harbour many cells with the requisite mutations and most will develop occult neoplastic lesions. Although essential for initiation, these mutations are not sufficient for the progression of cancer to a life-threatening disease. This progression appears to be dependent on context: the tissue ecosystem within individuals and lifestyle exposures across populations of individuals. Together, this implies that the seeds may be plentiful but they only germinate in the right soil. The incidence of these cancers is much lower in Eastern countries but is increasing with Westernisation and increases more acutely in migrants to the West. A Western lifestyle is strongly associated with perturbed metabolism, as evidenced by the epidemics of obesity and diabetes: this may also provide the setting enabling the progression of epithelial cancers. Epidemiology has indicated that metabolic biomarkers are prospectively associated with cancer incidence and prognosis. Furthermore, within cancer research, there has been a rediscovery that a switch in cell metabolism is critical for cancer progression but this is set within the metabolic status of the host. The seed may only germinate if the soil is fertile. This perspective brings together the different avenues of investigation implicating the role that metabolism may play within the context of post-genomic concepts of cancer.

The winding road to understanding the neonatal origins of inflammatory gastrointestinal disorders

Beginning with the observation that birth weight correlates with increased risk of cardiovascular disease, the concept of neonatal programming, that the environmental influence on fetal and neonatal development results in modification of the risk profile for adult disease, has begun to emerge as an important component to understanding the origin of chronic diseases of many different organ systems. Until recently, the gastrointestinal system has not been considered. Our understanding of the pathogenesis of many intestinal inflammatory disorders is still incomplete; however, a brief review of what is known reveals several opportunities for the early intraluminal environment to affect the development of the intestinal immune system. Early clinical observations such as the increased risk of celiac disease observed in those born by cesarean section and the protective effect of breast-feeding against inflammatory bowel disease and celiac disease support the role of neonatal programming in the development of chronic inflammatory gastrointestinal disease. Additional, more robust clinical studies are needed to confirm this role. Furthermore, examination of the possible mechanisms of immune phenotype modification is necessary.

Weight change in adulthood and risk of postmenopausal breast cancer: the HUNT study of Norway

BACKGROUND

Adult weight gain is associated with increased risk of postmenopausal breast cancer. Most previous studies are limited by using recalled or self-reported data, and it is not known if age-specific weight changes are important for breast cancer risk.

METHODS

In a Norwegian cohort of 28,153 women (and 900 incident breast cancers) with longitudinal anthropometric measurements over up to 30 years, we studied both overall and age-related weight changes in adulthood and risk of postmenopausal breast cancer.

RESULTS

Overall, weight gain in adulthood was associated with increased breast cancer risk (hazard ratio (HR) per kg per year 1.31, 95% confidence interval (CI) 1.11-1.54). Weight gain before (HR per kg per year 1.38, 95% CI 1.09-1.75) or around menopause (1.69, 95% CI 1.32-2.16) was associated with increased risk, but there was no clear risk increase associated with later weight gain (HR per kg per year 0.92, 95% CI 0.73-1.18).

CONCLUSION

Weight gain in adulthood was associated with increased risk of breast cancer. Our results suggest that weight gain before and around menopausal age may be particularly important for breast cancer risk among postmenopausal women.

Dietary soy effects on mammary gland development during the pubertal transition in nonhuman primates

While epidemiologic studies suggest that soy intake early in life may reduce breast cancer risk, there are also concerns that exposure to soy isoflavones during childhood may alter pubertal development and hormonal profiles. Here, we assessed the effect of a high-soy diet on pubertal breast development, sex hormones, and growth in a nonhuman primate model. Pubertal female cynomolgus monkeys were randomized to receive a diet modeled on a typical North American diet with one of two protein sources for approximately 4.5 years: (i) casein/lactalbumin (CL, n = 12, as control) or (ii) soy protein isolate with a human equivalent dose of 120 mg/d isoflavones (SOY, n = 17), which is comparable to approximately four servings of soy foods. Pubertal exposure to the SOY diet did not alter onset of menarche, indicators of growth and pubertal progression, or circulating estradiol and progesterone concentrations. Greater endometrial area was seen in the SOY group on the first of four postmenarchal ultrasound measurements (P < 0.05). There was a subtle effect of diet on breast differentiation whereby the SOY group showed higher numbers of differentiated large-sized lobular units and a lower proportion with immature ducts following menarche (P < 0.05). Numbers of small lobules and terminal end buds and mammary epithelial cell proliferation did not differ by diet. Expression of progesterone receptor was lower in immature lobules of soy-fed animals (P < 0.05). Our findings suggest that consumption of soy starting before menarche may result in modest effects consistent with a more differentiated breast phenotype in adulthood.

Epidemiology and prognosis of breast cancer in young women

Breast cancer is the most common malignancy in women with 6.6% of cases diagnosed in young women below the age of 40. Despite variances in risk factors, Age Standardized Incidence Rates of breast cancer in young women vary little between different countries. Review of modifiable risk factors shows that long-term use of oral contraceptives, low body mass index (BMI) and high animal fat diet consumption are associated with increased risk of premenopausal breast cancer. Decreased physical activity and obesity increase risks of breast cancer in postmenopausal women, but data on premenopausal women rather shows that high BMI is associated with decreased risk of breast cancer. Non-modifiable risk factors such as family history and genetic mutations do account for increased risks of breast cancer in premenopausal women. Breast cancer in young women is associated with adverse pathological factors, including high grade tumors, hormone receptor negativity, and HER2 overexpression. This has a significant negative impact on the rate of local recurrence and overall survival. Moreover, younger women often tend to present with breast cancer at a later stage than their older counterparts, which further explains worse outcome. Despite these factors, age per se is still being advocated as an independent role player in the prognosis. This entails more aggressive treatment modalities and the need for closer monitoring and follow-up.

Influences on the onset and tempo of puberty in human beings and implications for adolescent psychological development

This article is part of a Special Issue "Puberty and Adolescence". Historical records reveal a secular trend toward earlier onset of puberty in both males and females, often attributed to improvements in nutrition and health status. The trend stabilized during the mid 20th century in many countries, but recent studies describe a recurrence of a decrease in age of pubertal onset. There appears to be an associated change in pubertal tempo in girls, such that girls who enter puberty earlier have a longer duration of puberty. Puberty is influenced by genetic factors but since these effects cannot change dramatically over the past century, environmental effects, including endocrine disrupting chemicals (EDCs), and perinatal conditions offer alternative etiologies. Observations that the secular trends in puberty in girls parallel the obesity epidemic provide another plausible explanation. Early puberty has implications for poor behavioral and psychosocial outcomes as well as health later in life. Irrespective of the underlying cause of the ongoing trend toward early puberty, experts in the field have debated whether these trends should lead clinicians to reconsider a lower age of normal puberty, or whether such a new definition will mask a pathologic etiology.

Preadolescent and adolescent risk factors for benign breast disease

PURPOSE

It is well established that exposures during childhood and adolescence affect breast cancer risk much later in life. Recently, studies have begun to evaluate whether early life exposures might also impact the risk of developing benign breast disease (BBD). A diagnosis of proliferative BBD independent of other breast cancer risk factors also increases the subsequent risk of breast cancer; therefore, understanding how to decrease the incidence of BBD may have important implications for primary breast cancer prevention.

METHODS

We reviewed several studies from prospective cohort studies that have investigated the relationship between risk factors during childhood and adolescence, such as anthropometric and reproductive characteristics as well as diet and other behaviors, and subsequent risk of BBD.

RESULTS

Higher intake of vegetable oils, nuts, vitamin E, and fiber and lower consumption of animal fat, red meat, and alcohol are associated with reduced risk of BBD. Childhood weight and adolescent body mass index are inversely associated with BBD risk, whereas a greater peak height velocity during adolescence is associated with a higher risk of BBD. There was no association between age of menarche and risk of BBD.

CONCLUSION

Early life exposures and behaviors appear to impact BBD risk. The current body of evidence further supports the importance of a life-course approach to breast cancer prevention.

Dietary patterns and breast cancer risk among women in northern Tanzania: a case-control study

BACKGROUND

Breast cancer is the second most common cancer among women in the Kilimanjaro Region of Tanzania. It was tested within a case-control study in this region whether a specific dietary pattern impacts on the breast cancer risk.

METHODS

A validated semi-quantitative Food Frequency Questionnaire was used to assess the dietary intake of 115 female breast cancer patients and 230 healthy age-matched women living in the same districts. A logistic regression was performed to estimate breast cancer risk. Dietary patterns were obtained using principal component analysis with Varimax rotation.

RESULTS

The adjusted logistic regression estimated an increased risk for a "Fatty Diet", characterized by a higher consumption of milk, vegetable oils and fats, butter, lard and red meat (OR = 1.42, 95 % CI 1.08-1.87; P = 0.01), and for a "Fruity Diet", characterized by a higher consumption of fish, mango, papaya, avocado and watery fruits (OR = 1.61, 95 % CI 1.14-2.28; P = 0.01). Both diets showed an inverse association with the ratio between polyunsaturated and saturated fatty acids (P/S ratio).

CONCLUSION

A diet characterized by a low P/S ratio seems to be more important for the development of breast cancer than total fat intake.

Dairy intakes in older girls and risk of benign breast disease in young women

Previous investigations found high dairy intakes in girls associated with rapid height growth and excess weight gain, which had opposite relationships with benign breast disease (BBD) in young women. We use data from the longitudinal Growing Up Today Study (GUTS) to investigate whether dairy intakes, in older children/adolescents, are associated with BBD risk in young women. GUTS includes 9,039 females, ages 9-15 years in 1996, who completed questionnaires annually through 2001, then in 2003, 2005, 2007, and 2010. Dietary food frequencies (1996-2001) obtained milk, yogurt, and cheese intakes. On 2005-2010 surveys, 7,011 females (18-29 years) reported whether a health care provider ever diagnosed them with BBD (n = 250) and if confirmed by breast biopsy (n = 105). Logistic regression models estimated associations between prevalent biopsy-confirmed BBD and dairy intakes, adjusted for age and energy. Multivariable-adjusted models additionally included menarche age, childhood adiposity, adolescent alcohol consumption, and pregnancy. Further analyses stratified by family history. Age-energy-adjusted models of dairy (milk, yogurt, cheese, total dairy servings, dairy protein, dairy fat) intakes at 14 yr found no significant associations with BBD risk [milk: OR, 0.90/(serving/d); 95% confidence interval (CI), 0.76-1.05; dairy protein: OR, 0.98/(10 g/d); 95% CI, 0.82-1.17). Separate analyses of dairy intakes at 10 yr, intakes before the growth spurt, during the growth spurt, before menses-onset, and after menses-onset provided no significant associations with BBD. Multivariable adjustment, and family history stratification, did not alter the above findings. We conclude that dairy intakes by older girls have no strong relation with BBD risk in young women. Because of small number of cases, it is important to continue follow-up and re-examine later.

Reduced risk of breast, endometrial and ovarian cancer in women with celiac disease

Women with celiac disease (CD) may be at decreased risk of female hormone‐related cancers given the observed reduction in breast cancer seen in some cohorts. Using biopsy data from all 28 pathology departments in Sweden, we identified 17,852 women with CD who were diagnosed between 1969 and 2007. We used Cox regression model to estimate their risk of breast, endometrial and ovarian cancer and then compared them with 88,400 age‐ and sex‐matched controls. The results indicate that individuals with CD were at a lower risk for all three outcomes: breast cancer (hazard ratio, HR = 0.85; 95% CI = 0.72–1.01), endometrial cancer (HR = 0.60; 95% CI =0.41–0.86) and ovarian cancer (HR = 0.89; 95% CI =0.59–1.34). This inverse relationship was strengthened when we excluded the first year of follow‐up beyond CD diagnosis (breast: HR = 0.82; 95% CI =0.68–0.99; endometrial: HR = 0.58; 0.39–0.87; ovarian cancer: HR = 0.72; 0.45–1.15). In conclusion, CD seems to be inversely related not only to breast cancer but also to endometrial and ovarian cancer. Potential explanations include shared risk factors and early menopause.

Insulin-like growth factor receptor inhibitors: baby or the bathwater?

The success of targeted therapies for cancer is undisputed; strong preclinical evidence has resulted in the approval of several new agents for cancer treatment. The type I insulin-like growth factor receptor (IGF1R) appeared to be one of these promising new targets. Substantial population and preclinical data have all pointed toward this pathway as an important regulator of tumor cell biology. Although early results from clinical trials that targeted the IGF1R showed some evidence of response, larger randomized phase III trials have not shown clear clinical benefit of targeting this pathway in combination with conventional strategies. These disappointing results have resulted in the discontinuation of several anti-IGF1R programs. However, the conduct of these trials has brought to the forefront several important factors that need to be considered in the conduct of future clinical trials. The need to develop biomarkers, a clearer understanding of insulin receptor function, and defining rational combination regimens all require further consideration. In this commentary, the current state of IGF1R inhibitors in cancer therapy is reviewed.

Breast cancer in young women

About one in 300 women will be diagnosed with breast cancer before the age of 40. Advances in screening have not had an impact on mortality in women who are too young to be candidates for screening. Risk factors for early breast cancer include a lean body habitus and recent use of an oral contraceptive. Breast cancers in very young women are typically aggressive, in part owing to the over-representation of high-grade, triple-negative tumours, but young age is an independent negative predictor of cancer-specific survival. Very early age-of-onset also correlates strongly with the risk of local recurrence and with the odds of contralateral breast cancer. Given the high risks of local and distant recurrence in young women with invasive breast cancer, most (if not all) young patients are candidates for chemotherapy. It is hoped that by increasing breast cancer awareness, the proportion of invasive breast cancers that are diagnosed at 2.0 cm or smaller will increase and that this will lead to a reduction in mortality.

Leg length, sitting height and postmenopausal breast cancer risk

Background:

Tallness has consistently been associated with an increased risk of breast cancer. We investigated the association further by decomposing height into leg length and sitting height.

Methods:

From the prospective Danish cohort ‘Diet, Cancer and Health’, 23 864 postmenopausal women enrolled during 1993–1997 were followed for a diagnosis of breast cancer in the Danish Cancer Registry through 2009.

Results:

The incidence rate ratios for breast cancer were 1.11 (95% CI=1.06–1.16) for each 5 cm increase in total height and 1.09 (95% CI=1.01–1.17) and 1.14 (95% CI=1.04–1.25) for each 5 cm increase in leg length and sitting height, respectively. There was no statistical significant difference between the associations for leg length and sitting height (P=0.47).

Conclusion:

Leg length does not seem to be more strongly associated with breast cancer among postmenopausal women than sitting height.

Fetal programming of adult disease: implications for prenatal care

The obesity epidemic, including a marked increase in the prevalence of obesity among pregnant women, represents a critical public health problem in the United States and throughout the world. Over the past two decades, it has been increasingly recognized that the risk of adult health disorders, particularly metabolic syndrome, can be markedly influenced by prenatal and infant environmental exposures (ie, developmental programming). Low birth weight, together with infant catch-up growth, is associated with a significant risk of adult obesity and cardiovascular disease, as well as adverse effects on pulmonary, renal, and cerebral function. Conversely, exposure to maternal obesity or high birth weight also represents an increased risk for childhood and adult obesity. In addition, fetal exposure to select chemicals (eg, phytoestrogens) or environmental pollutants (eg, tobacco smoke) may affect the predisposition to adult disease. Animal models have confirmed human epidemiologic findings and provided insight into putative programming mechanisms, including altered organ development, cellular signaling responses, and epigenetic modifications (ie, control of gene expression without modification of DNA sequence). Prenatal care is transitioning to incorporate goals of optimizing maternal, fetal, and neonatal health to prevent or reduce adult-onset diseases. Guidelines regarding optimal pregnancy nutrition and weight gain, management of low- and high-fetal-weight pregnancies, use of maternal glucocorticoids, and newborn feeding strategies, among others, have yet to fully integrate long-term consequences on adult health.

Alterations in Brca1 expression in mouse ovarian granulosa cells have short-term and long-term consequences on estrogen-responsive organs

Incessant menstrual cycle activity, uninterrupted by either pregnancy or oral contraceptive use, is the most important risk factor for sporadic ovarian cancer. Menstrual cycle progression is partly controlled by steroid hormones such as estrogens and others that are secreted by the ovarian granulosa cells. We showed earlier that mice carrying a homozygous granulosa cell-specific knockout of Brca1, the homolog of BRCA1 that is associated with familial ovarian cancer predisposition in humans, develop benign epithelial tumors in their reproductive tract. These tumors are driven, at least in part, by a prolongation of the proestrus phase of the estrus cycle (equivalent to the follicular phase of the menstrual cycle) in Brca1 mutant mice, resulting in prolonged unopposed estrogen stimulation. Mutant mice synchronized in proestrus also showed increased circulating estradiol levels, but the possibility that this change also has a role in tumor predisposition was not investigated. We sought to determine whether these changes in hormonal stimulation result in measurable changes in tissues targeted by estrogen outside the ovary. Here we show that mice carrying a Brca1 mutation in their ovarian granulosa cells show increased endometrial proliferation during proestrus, implying that the effects of Brca1 inactivation on estrogen stimulation have short-term consequences, at least on this target organ. We further show that mutant mice develop increased femoral trabecular thickness and femoral length, which are well-known consequences of chronic estrogen stimulation. Estrogen biosynthesis by granulosa cells was increased not only in mice carrying a homozygous Brca1 mutation, but also in heterozygous mutants mimicking the mutational status in granulosa cells of human BRCA1 mutation carriers. The results suggest that human germline BRCA1 mutations, although associated with increased cancer risk, may also have beneficial consequences, such as increased bone strength, that may have contributed to the maintenance of mutated BRCA1 alleles in the human gene pool.

Targeting the insulin growth factor receptor 1

The IGF axis is a tightly controlled endocrine system that regulates cell growth and development, known to have an important function in cancer biology. IGF1 and IGF2 can promote cancer growth in a GH-independent manner both through paracrine and autocrine secretion and can also confer resistance to chemotherapy and radiation. Many alterations of this system have been found in neoplasias, including increased expression of ligands and receptors, loss of heterozygosity of the IGF2 locus and increased IGF1R gene copy number. The IGF1 network is an attractive candidate for targeted therapy, including receptor blockade with monoclonal antibodies and small molecule inhibitors of receptor downstream signaling. This article reviews the role of the IGF axis in the initiation and progression of cancer, and describes the recent advances in IGF inhibition as a therapeutic tool.

Occurrence and timing of childhood overweight and mortality: findings from the Third Harvard Growth Study

OBJECTIVE

To assess the mortality experience of participants in the Third Harvard Growth Study (1922-1935) who provided ≥ 8 years of growth data.

STUDY DESIGN

A total of 1877 participants provided an average of 10.5 body mass index measurements between age 6 and 18 years. Based on these measurements, the participants were classified as ever overweight or ever >85th percentile for height in childhood. Age at peak height velocity was used to indicate timing of overweight relative to puberty. Relative risks of all-cause and cause-specific mortality according to measures of childhood growth were estimated using Cox proportional hazards survival analysis.

RESULTS

For women, ever being overweight in childhood increased the risks of all-cause and breast cancer death; the risk of death from ischemic heart disease was increased in men. Men with a first incidence of overweight before puberty were significantly more likely to die from ischemic heart disease; women in the same category were more likely to die from all causes and from breast cancer.

CONCLUSION

We find evidence of long-term effects of having ever been overweight, with some evidence that incidence before puberty influences the pattern of risk.

Early nutrition impact on the insulin-like growth factor axis and later health consequences

PURPOSE OF REVIEW

There is increasing interest in the role of insulin-like growth factor-I (IGF-I) in the relation between early growth and later risk of noncommunicable diseases (NCDs). This review presents and discusses a selection of recent publications on this topic.

RECENT FINDINGS

Nutrition during pregnancy and in preterm infants has an influence on IGF-I. Breastfeeding is associated with lower IGF-I values and the effect of early protein intake was confirmed in a large intervention study. IGF-I levels are associated with early obesity, but the relation is complex and differs with age. Further studies and reviews support that there is a programming of the IGF axis, with higher levels during early life being associated with lower levels in adulthood, which is likely to influence the risk of NCDs later in life.

SUMMARY

Recent studies support that IGF-I plays an important role in the complex association between early diet, growth and later health, but more studies are needed to better understand the role of IGF-I, especially in the early development of obesity. Studies with data on how IGF-I is influenced by early diet in studies of preterm infants and young children with undernutrition from low-income countries will be helpful in recommending optimal diets.

The Susan G. Komen for the Cure Tissue Bank at the IU Simon Cancer Center: a unique resource for defining the "molecular histology" of the breast

"Molecular histology" of the breast may be conceptualized as encompassing the normative ranges of histologic structure and marker expression in normal breast tissues in relation to a woman's age and life experiences. Studies of molecular histology can aid our understanding of early events in breast carcinogenesis and provide data for comparison with diseased breast tissues. Until recently, lack of epidemiologically annotated, optimally prepared normal breast tissues obtained from healthy women presented a barrier to breast cancer research. The Komen Tissue Bank at Indiana University (Indianapolis, IN) is a unique biorepository that was developed to overcome this limitation. The Bank enrolls healthy donors who provide questionnaire data, blood, and up to four breast biopsies, which are prepared as both formalin-fixed, paraffin-embedded and frozen tissues. The resource is accessible to researchers worldwide through a proposal submission, review, and approval process. As of November 2010, the Bank had collected specimens and information from 1,174 donors. In this review, we discuss the importance of studying normal breast tissues, assess the strengths and limitations of studying normal tissues obtained from different sources, and summarize the features of the Komen Tissue Bank. As research projects are completed, results will be posted on the Bank's website.

The Changes They are A-Timed: Metabolism, Endogenous Clocks, and the Timing of Puberty

Childhood obesity has increased dramatically over the last several decades, particularly in industrialized countries, often accompanied by acceleration of pubertal progression and associated reproductive abnormalities (Biro et al., 2006; Rosenfield et al., 2009). The timing of pubertal initiation and progression in mammals is likely influenced by nutritional and metabolic state, leading to the hypothesis that deviations from normal metabolic rate, such as those seen in obesity, may contribute to observed alterations in the rate of pubertal progression. While several recent reviews have addressed the effects of metabolic disorders on reproductive function in general, this review will explore previous and current models of pubertal timing, outlining a potential role of endogenous timing mechanisms such as cellular circadian clocks in the initiation of puberty, and how these clocks might be altered by metabolic factors. Additionally, we will examine recently elucidated neuroendocrine regulators of pubertal progression such as kisspeptin, explore models detailing how the mammalian reproductive axis is silenced during the juvenile period and reactivated at appropriate developmental times, and emphasize how metabolic dysfunction such as childhood obesity may alter timing cues that advance or delay pubertal progression, resulting in diminished reproductive capacity.

Being breastfed in infancy and adult breast cancer risk among Japanese women

OBJECTIVE

Being breastfed in infancy has been hypothesized to influence subsequent breast cancer risk. In a hospital-based case-control study, we investigated the relationship between having been breastfed and breast cancer risk, both overall and separately among female subjects with different birth years.

METHODS

The study subjects included 571 cases and 2,155 controls admitted to a single hospital in Miyagi Prefecture, Japan, between 1997 and 2005. History of having been breastfed was assessed with a self-administered questionnaire. Odds ratios (ORs) and 95% confidence interval (CI) were estimated using logistic regression.

RESULTS

After adjustment for known risk factors, no association for having been breastfed was observed overall (OR = 1.20; 95% CI: 0.82-1.76). Analysis stratified according to birth year (<1950, ≥1950) demonstrated heterogeneity in the association for having been breastfed between the two birth-year groups (p for interaction = 0.0006); having been breastfed was significantly associated with a decreased risk among subjects who were born before 1950 (OR = 0.59; 95% CI: 0.35-0.99), whereas no such risk reduction was observed for subjects born after 1950 (OR = 1.60; 95% CI: 0.88-2.90).

CONCLUSION

Although having been breastfed is not related to overall risk, birth year may modify the association between having been breastfed in infancy and breast cancer risk. In Japan, sociodemographic changes have occurred since the end of World War II. The use of standard formula supplement began to spread around 1950. The difference of breast cancer risk between birth-year groups may be attributable to these environmental changes.

Young women with family history of breast cancer and their risk factors for benign breast disease

BACKGROUND

Breast cancer (BC) patients wonder how their daughters might reduce their risk. The authors investigated childhood/adolescent risk factors for benign breast disease (BBD), a well-documented risk factor for BC, among girls with a family history.

METHODS

GUTS (the Growing Up Today Study) includes females, aged 9 to 15 years in 1996, who completed annual questionnaires during 1996 to 2001, then in 2003, 2005, and 2007. Participants provided information regarding alcohol, menarche, height, and body mass index (BMI; kg/m(2)). Peak height growth velocity (PHV; in./y) was estimated from longitudinal heights. On 2005-2007 surveys, 6888 women (18-27 years old) reported whether they were diagnosed with biopsy-confirmed BBD (n = 67 cases); 6741 women (noncases) reported no BBD. Participants' mothers reported their own biopsy-confirmed BBD and BC, and BC in their sisters and mothers. Stratified by family history, logistic models investigated BBD risk factors.

RESULTS

Young women whose mothers or aunts had BC were more likely to be diagnosed with BBD (odds ratio [OR], 2.34; P = .01), as were those with maternal BBD (OR, 1.59; P = .095). Adolescents with BC family history (mother, aunt, grandmother) who consumed alcohol (7 drinks/wk) doubled their BBD risk (OR, 2.28; P = .01), similar to those with maternal BBD (OR, 1.96; P = .02). Girls whose mother or aunt had BC saw their BBD risk elevated with higher PHV (OR, 1.82 [inch/yr]; P = .05). Among girls with no family history, BBD risk appeared to be related to other factors: childhood BMI, adolescent waist circumference, and adult height.

CONCLUSIONS

Adolescents with family history may reduce their risk by avoiding alcohol. Separate risk factors were observed among girls with family history versus girls with no family history, possibly reflecting different causes of BC.

Associations of birth weight and physical activity with sex steroids in preschool Japanese children

PURPOSE

We aimed to assess the association of body size at birth or physical activity with sex steroid levels, independent of body mass among young children.

METHODS

The cross-sectional study was conducted in 2006. Subjects were 230 boys and 198 girls, aged 3-6 years. Birth weight was based on parents' reports. Questions about physical activity focused on outdoor playtime. Urinary estrone, estradiol, testosterone, and 5-androstene-3β,17α diol (3β,17α-AED) levels were measured by liquid chromatography-electrospray ionization tandem mass spectrometry. Urinary dehydroepiandrosterone level was measured with a radioimmunoassay.

RESULTS

After adjustments for age and BMI, girls with lower birth weight had higher testosterone (trend p = 0.038) and 3β,17α-AED (trend p = 0.028). Girls with low birth weight and high birth weight had higher estrone (p = 0.014) and estradiol (p = 0.074) than those who had middle birth weight. Boys who were physically active had lower testosterone (p = 0.028) and 3β,17α-AED (p = 0.003) than those who were not active. Girls who were physically active had lower estrone (p = 0.015).

CONCLUSIONS

Sex steroid levels in childhood might be affected by body size at birth or by physical activity during childhood. These effects might differ by sex.