Vegetable protein and vegetable fat intakes in pre-adolescent and adolescent girls, and risk for benign breast disease in young women

Investigating the Link between Early Life and Breast Anomalies

Several factors during childhood and adolescence are thought to be associated with the development of proliferative benign breast diseases and breast cancer in adulthood. In order to identify them, the authors conducted an extensive review of the literature up to October 2022, searching for clinical studies, reports, and guidelines in English. A thorough Medline/Pubmed and Google scholar database research was performed, investigating the link between diet, exercise, age of menarche, body mass index, ionizing radiation exposure during childhood and adolescence, and proliferative breast diseases and breast cancer in adulthood. A list of keywords, including breast disorders, adolescence, childhood, and breast cancer was included in our search algorithm. Numerous studies concede that the development of breast disease in adulthood is influenced by various risk factors, whose influence begins during early childhood and adolescence.

Cancer Risk Reduction Through Education of Adolescents: Development of a Tailored Cancer Risk-Reduction Educational Tool

Growing evidence links adolescent exposures to cancer risk later in life, particularly for common cancers like breast. The adolescent time period is also important for cancer risk reduction as many individual lifestyle behaviors are initiated including smoking and alcohol use. We developed a cancer risk-reduction educational tool tailored for adolescents that focused on five modifiable cancer risk factors. To contextualize risk factors in adolescents' social and physical environments, the intervention also focused on structural barriers to individual- and community-level change, with an emphasis on environmental justice or the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. The educational tool consisted of a 50-min module that included an introduction to cancer biology including genetic susceptibility and environmental interactions, cancer burden in the local community, and risk reduction strategies. The module also included an interactive activity in which adolescent students identify cancer risk factors and brainstorm strategies for risk reduction at both the individual and community level. We administered the module to 12 classes of over 280 high school and college students in New York City. Cancer risk reduction strategies identified by the students included family- or peer-level strategies such as team physical activity and community-level action including improving parks and taxing sugary foods. We developed a novel and interactive cancer risk-reduction education tool focused on multiple cancers that can be adopted by other communities and educational institutions.

Adolescent Plant Product Intake in Relation to Later Prostate Cancer Risk and Mortality in the NIH-AARP Diet and Health Study

BACKGROUND

Although fruit and vegetable intake during adolescence, a potentially sensitive time period for prostate cancer (PCa) development, has been proposed to protect against PCa risk, few studies have investigated the role of adolescent plant product intake in PCa development.

METHODS

Intake of various vegetables, fruit, and grains by males at ages 12-13 y was examined in relation to later PCa risk and mortality in the NIH-AARP Diet and Health Study. Cox proportional hazards regression was used to calculate HRs and 95% CIs of nonadvanced (n = 14,238) and advanced (n = 2,170) PCa incidence and PCa mortality (n = 760) during 1,729,896 person-years of follow-up.

RESULTS

None of the plant products examined were associated consistently with all PCa outcomes. However, greater adolescent intakes of tomatoes (P-trend = 0.004) and nonstarch vegetables (P-trend = 0.025) were associated with reduced risk of nonadvanced PCa, and greater intakes of broccoli (P-trend = 0.050) and fruit juice (P-trend = 0.019-0.025) were associated with reduced risk of advanced PCa and/or PCa mortality. Positive trends were also observed for greater intakes of fruit juice (P-trend = 0.002), total fruit (P-trend = 0.014), and dark bread (P-trend = 0.035) with nonadvanced PCa risk and for greater intakes of legumes (P-trend < 0.001), fiber (P-trend = 0.001), and vegetable protein (P-trend = 0.013-0.040) with advanced PCa risk or PCa mortality.

CONCLUSIONS

Our findings do not provide strong evidence to suggest that adolescent plant product intake is associated with reduced PCa risk.

Association of Total Nut, Tree Nut, Peanut, and Peanut Butter Consumption with Cancer Incidence and Mortality: A Comprehensive Systematic Review and Dose-Response Meta-Analysis of Observational Studies

Data on the association of nut intake with risk of cancer and its mortality are conflicting. Although previous meta-analyses summarized available findings in this regard, some limitations may distort their findings. Moreover, none of these meta-analyses examined the dose-response associations of total nut intake with the risk of specific cancers as well as associations between specific types of nuts and cancer mortality. Therefore, this study aimed to summarize available findings on the associations of total nut (tree nuts and peanuts), tree nut (walnuts, pistachios, macadamia nuts, pecans, cashews, almonds, hazelnuts, and Brazil nuts), peanut (whole peanuts without considering peanut butter), and peanut butter consumption with risk of cancer and its mortality by considering the above-mentioned points. We searched the online databases until March 2020 to identify eligible articles. In total, 43 articles on cancer risk and 9 articles on cancer mortality were included in the current systematic review and meta-analysis. The summary effect size (ES) for risk of cancer, comparing the highest with lowest intakes of total nuts, was 0.86 (95% CI: 0.81, 0.92, P < 0.001, I2 = 58.1%; P < 0.01), indicating a significant inverse association. Such a significant inverse association was also seen for tree nut intake (pooled ES: 0.87, 95% CI: 0.78-0.96, P < 0.01, I2 = 15.8%; P = 0.28). Based on the dose-response analysis, a 5-g/d increase in total nut intake was associated with 3%, 6%, and 25% lower risks of overall, pancreatic, and colon cancers, respectively. In terms of cancer mortality, we found 13%, 18%, and 8% risk reductions with higher intakes of total nuts, tree nuts, and peanuts, respectively. In addition, a 5-g/d increase in total nut intake was associated with a 4% lower risk of cancer mortality. In conclusion, our findings support the protective association between total nut and tree nut intake and the risk of cancer and its mortality.

Reproducibility and Validity of a Food Frequency Questionnaire for Dietary Assessment in Adolescents in a Self-Reported Way

Tools to assess diet in a reliable and efficient way are needed, particularly in children and adolescents. In this study, we assess the reproducibility and validity of a semiquantitative food frequency questionnaire (FFQ) among adolescents in Spain. We analyzed data of 51 male adolescents aged 15-17 years from a prospective birth cohort study. Participants answered the FFQ twice in a self-administered way over a 12-month period. Reproducibility was assessed by comparing nutrient and food intakes from the FFQs, and validity by comparing nutrient intakes from the average of two FFQs and the average of two 24-Hour Dietary Recalls obtained in the period. Pearson correlation coefficients were calculated. The average of reproducibility correlation coefficients for food group intakes was 0.33, with the highest correlation for vegetable intake (r = 0.81); and the average for nutrient intake was 0.32, with the highest coefficients for α- and β-carotene (r = 0.65). Validity correlation coefficients ranged from 0.07 for carbohydrates to 0.53 for dietary fiber. The average of the validity correlation coefficients was r = 0.32. This study suggests that our FFQ may be a useful tool for assessing dietary intake of most nutrient and food groups among Spanish male adolescents in a self-administered way, despite reproducibility and, particularly validity, being low for some nutrients and food groups.

Dairy consumption during adolescence and endometriosis risk

BACKGROUND

Modifiable risk factors such as diet may be important in both the etiology and progression of endometriosis as well as the prevalence of pain symptoms and infertility associated with this condition. In adults, higher intake of dairy has been associated with a lower risk of endometriosis diagnosis. There is currently no literature on whether dairy intake during adolescence, a potentially critical window of exposure, influences endometriosis risk.

OBJECTIVE

The objectige of the study was to evaluate the association between consumption of dairy foods in adolescence and the risk of laparoscopically confirmed endometriosis.

STUDY DESIGN

This was a prospective cohort study, the Nurses' Health Study II, which has prospectively collected data since 1989. In 1998, when participants were aged 34-51 years, they completed a 124 item food frequency questionnaire about their high school diet. Cases were defined as those who self-reported laparoscopically confirmed endometriosis. Cox proportional hazard models were used to calculate hazard ratios and 95% confidence intervals for the association between dairy foods and laparoscopically confirmed endometriosis.

RESULTS

Among women who completed the questionnaire about their high school diet in 1998, 581 cases of laparoscopically confirmed endometriosis were diagnosed among 32,868 premenopausal women from 1998 to 2013. Women who consumed more than 4 servings per day of dairy foods during adolescence had a 32% lower risk of laparoscopically confirmed endometriosis during adulthood (95% confidence interval, 0.47-0.96; P_trend = .04) compared with women consuming 1 or fewer servings per day. The association was similar for low-fat and high-fat dairy foods. Yogurt and ice cream consumption, specifically, were associated with a lower risk of endometriosis. Those who consumed 2 or more servings of yogurt per week as an adolescent had a 29% lower risk of endometriosis diagnosis (95% confidence interval, 0.52-0.97; P_trend = .02) compared with those consuming less than 1 serving per week. In addition, women who consumed 1 or more servings per day of ice cream per day during adolescence had a 38% lower risk of endometriosis diagnosis (95% confidence interval, 0.40-0.94; P_trend = .20) compared with those consuming less than 1 serving per week.

CONCLUSION

Our findings suggest that dairy consumption, specifically yogurt and ice cream intake, in adolescence may reduce the risk of subsequent endometriosis diagnosis. Future studies in adolescent populations are needed to confirm these results.

Higher Dietary Inflammatory Index Scores are Associated with Increased Odds of Benign Breast Diseases in a Case-Control Study

Purpose

Dietary inflammatory index (DII) is a new tool for assessing the inflammatory potential of diet. Since there is no study that has investigated the association of DII and benign breast diseases (BBD), the aim of our study was to compare DII scores in patients with and without BBD.

Methods

One hundred and eleven (111) subjects with BBD and 104 healthy women attending the Iranian Center for Breast Cancer affiliated with the Academic Center for Education, Culture and Research were enrolled in a case–control study. Dietary data collected using a 168‑item validated food frequency questionnaire (FFQ). Energy-adjusted DII was calculated based on FFQ. Socio demographic data were collected by interview. In addition, physical activity was measured by the International Physical Activity Questionnaire (IPAQ). Weight, height and waist circumference were also measured.

Results

After adjustment for multiple confounding variables, participants at the highest tertile of DII had increased OR for BBD (OR=1.7, 95% CI=0.75–3.95) (P-trend =0.04).

Conclusion

The increased chance of BBD was suggested with a higher consumption of diets with inflammatory potential. However, this result should be interpreted with caution as OR was not statistically significant. Interventional studies are warranted to elucidate the role of inflammatory diets in the development of BBD.

Dietary intake from birth through adolescence in relation to risk of benign breast disease in young women

PURPOSE

Nutritional factors during different periods in life impact breast cancer risk. Because benign breast disease (BBD) is a well-established risk factor for breast cancer, we investigated childhood nutrition from birth through age 14 year and subsequent BBD.

METHODS

A prospective cohort study of 9031 females, 9-15 year at baseline, completed questionnaires (including heights, weights) annually from 1996 to 2001, in 2003, 2005, 2007, 2010, 2013 and 2014. In 1996, mothers reported infant feeding practices during their daughters first year of life. Beginning in 1996, participants completed annual food frequency questionnaires. In 2005, participants (18 year +) began reporting whether they had ever been diagnosed with biopsy-confirmed BBD (N = 173 cases). Multivariable logistic regression models estimated associations between childhood nutrition and BBD, adjusted for maternal breast disease and childhood body size factors.

RESULTS

Although no infant nutrition factors were associated with biopsy-confirmed BBD, certain adolescent dietary factors were. A multivariable model simultaneously included the most important diet and body size factors from different age periods: higher BBD risk was associated with greater age 10 year consumption of animal (non-dairy, energy-adjusted) fat (OR 2.27, p < .02, top vs. bottom quartiles) and with lower 14 year consumption of nuts/peanut butter (OR 0.60, p = .033, top vs. bottom quartiles).

CONCLUSION

Greater intake of animal (non-dairy) fat at 10 year and lower intake of nuts/peanut butter at 14 year were independently associated with higher BBD risk. These dietary factors appeared to operate on BBD risk independent of childhood growth (gestational weight gain, childhood BMI and height, adolescent height growth velocity), young adult height and BMI, and family history.

Psychosocial stress is associated with benign breast disease in young Chinese women: results from Project ELEFANT

PURPOSE

Psychosocial stress, including bereavement and work-related stress, is associated with the risk of breast cancer. However, it is unknown whether it may also be linked with increased risk of benign breast disease (BBD).

METHODS

Our study leveraged 61,907 women aged 17-55 years old from the Project ELEFANT study. BBD was diagnosed by clinician. Self-reported data on psychosocial stress over a 10-year period was retrospectively collected from questionnaires and categorised by cause (work, social and economic) and severity (none, low and high). Odd ratios (ORs) for the development of BBD were estimated using logistic regression. The model was adjusted for age, BMI, TSH levels, smoking, alcohol consumption, family history, age of menarche, oral contraceptive usage, education and occupation.

RESULTS

Within our study, 8% (4,914) of participants were diagnosed with BBD. Work-related stress [OR 1.57, 95% confidence interval (CI) 1.46-1.69] and financial stress (OR 1.34, 95% CI 1.24-1.44) were significantly associated with BBD incidence, with a smaller but still significant association with social stress (OR 1.11, 95% CI 1.01-1.21). The associations remained significant after exclusion of participants with first- and second-degree family history of breast disease. The presence of multiple forms of stress did not synergistically increase risk. The neutrophil-lymphocyte ratio (NLR), a marker of systemic inflammation and prognostic marker for breast cancer, was not associated with BBD.

CONCLUSIONS

Psychosocial stress, particularly work-related and financial stress, is associated with increased risk of benign breast disease among young Chinese women.

Association between whole grain intake and breast cancer risk: a systematic review and meta-analysis of observational studies

Background

Epidemiological studies have found that high whole grain intake may be associated with a reduced risk of breast cancer. However, the evidence has not been consistent. We conducted a meta-analysis to quantitatively assess the association between whole grain intake and breast cancer risk.

Methods

Relevant observational studies were identified by searching PubMed, Embase, Cochrane library databases, and Google Scholar through April 2017. Summary relative risk (RR) estimates were calculated using random-effects meta-analysis.

Results

A total of 11 studies, including 4 cohort and 7 case-control studies and involving 131,151 participants and 11,589 breast cancer cases, were included in the current meta-analysis. The pooled RR of breast cancer for those with high versus low whole grain intake was 0.84 (95% confidence interval [CI]: 0.74 to 0.96, p = 0.009; I² = 63.8%, p_{for heterogeneity} = 0.002). Subgroup analysis by study design found a significant inverse association in the case-control studies (RR: 0.69; 95% CI: 0.56 to 0.87, p = 0.001; I² = 58.2%, p _{for heterogeneity} = 0.026), but not in the cohort studies (RR, 0.96; 95% CI: 0.82 to 1.14, p = 0.69; I² = 66.7%, p for heterogeneity = 0.029). In addition, stratified analysis suggested that sample size could be a potential source of heterogeneity.

Conclusions

Results of the current meta-analysis suggest that high intake of whole grains might be inversely associated with a reduced risk of breast cancer, and the inverse association was only observed in case-control but not cohort studies. More large-scale cohort studies are needed to confirm the inverse association observed.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0394-2) contains supplementary material, which is available to authorized users.

Early Life Exposures and Adult Cancer Risk

Very little is known about the influence of early life exposures on adult cancer risk. The purpose of this narrative review was to summarize the epidemiologic evidence relating early life tobacco use, obesity, diet, and physical activity to adult cancer risk; describe relevant theoretical frameworks and methodological strategies for studying early life exposures; and discuss policies and research initiatives focused on early life. Our findings suggest that in utero exposures may indirectly influence cancer risk by modifying biological pathways associated with carcinogenesis; however, more research is needed to firmly establish these associations. Initiation of exposures during childhood and adolescence may impact cancer risk by increasing duration and lifetime exposure to carcinogens and/or by acting during critical developmental periods. To expand the evidence base, we encourage the use of life course frameworks, causal inference methods such as Mendelian randomization, and statistical approaches such as group-based trajectory modeling in future studies. Further, we emphasize the need for objective exposure biomarkers and valid surrogate endpoints to reduce misclassification. With the exception of tobacco use, there is insufficient evidence to support the development of new cancer prevention policies; however, we highlight existing policies that may reduce the burden of these modifiable risk factors in early life.

Relative validity of a web-based food frequency questionnaire for Danish adolescents

Background

With increased focus on dietary intake among youth and risk of diseases later in life, it is of importance, prior to assessing diet-disease relationships, to examine the validity of the dietary assessment tool. This study’s objective was to evaluate the relative validity of a self-administered web-based FFQ among Danish children aged 12 to 15 years.

Methods

From a nested sub-cohort within the Danish National Birth Cohort, 124 adolescents participated. Four weeks after completion of the FFQ, adolescents were invited to complete three telephone-based 24HRs; administered 4 weeks apart. Mean or median intakes of nutrients and food groups estimated from the FFQ were compared with the mean of 3x24HRs. To assess the level of ranking we calculated the proportion of correctly classified into the same quartile, and the proportion of misclassified (into the opposite quartile). Spearman’s correlation coefficients and de-attenuated coefficients were calculated to assess agreement between the FFQ and 24HRs.

Results

The mean percentage of all food groups, for adolescents classified into the same and opposite quartile was 35 and 7.5%, respectively. Mean Spearman’s correlation was 0.28 for food groups and 0.35 for nutrients, respectively. Adjustment for energy and within-person variation in the 24HRs had little effect on the magnitude of the correlations for food groups and nutrients. We found overestimation by the FFQ compared with the 24HRs for fish, fruits, vegetables, oils and dressing and underestimation by the FFQ for meat/poultry and sweets. Median intake of beverages, dairy, bread, cereals, the mean total energy and carbohydrate intake did not differ significantly between the two methods.

Conclusion

The relative validity of the FFQ compared with the 3x24HRs showed that the ranking ability differed across food groups and nutrients with best ranking for estimated intake of dairy, fruits, and oils and dressing. Larger variation was observed for fish, sweets and vegetables. For nutrients, the ranking ability was acceptable for fatty acids and iron. When evaluating estimates from the FFQ among Danish adolescents these findings should be considered.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0312-7) contains supplementary material, which is available to authorized users.

Tree nut, peanut, and peanut butter intake and risk of postmenopausal breast cancer: The Netherlands Cohort Study

PURPOSE

Nut intake has been associated with reduced mortality and risk of cardiovascular diseases, but there is only limited evidence on cancer. We investigated the relationship between nut intake and risk of postmenopausal breast cancer, and estrogen/progesterone receptor (ER/PR) subtypes.

METHODS

In The Netherlands Cohort Study, 62,573 women aged 55-69 years provided information on dietary and lifestyle habits in 1986. After 20.3 years of follow-up, 2,321 incident breast cancer cases and 1,665 subcohort members were eligible for multivariate case-cohort analyses.

RESULTS

Total nut intake was significantly inversely related to ER negative (ER -) breast cancer risk, with HR 0.55 (95% CI 0.33-0.93) for those consuming at least 10 g nuts/day versus non-consumers (p trend = 0.025). There were no significant inverse associations with ER + or total breast cancer. While there was no variation between PR subtypes, the ER-PR- subtype was also significantly inversely associated with nut intake, with HR 0.53 (95% CI 0.29-0.99), p trend = 0.037. Intake of peanuts and tree nuts separately was also inversely related to ER - breast cancer subtypes, while no associations were found with peanut butter intake.

CONCLUSIONS

Our findings suggest an inverse association between nut intake and ER - breast cancer, and no association with total or hormone receptor-positive subtypes.

Tree nut, peanut, and peanut butter intake and risk of postmenopausal breast cancer: The Netherlands Cohort Study

PURPOSE

Nut intake has been associated with reduced mortality and risk of cardiovascular diseases, but there is only limited evidence on cancer. We investigated the relationship between nut intake and risk of postmenopausal breast cancer, and estrogen/progesterone receptor (ER/PR) subtypes.

METHODS

In The Netherlands Cohort Study, 62,573 women aged 55-69 years provided information on dietary and lifestyle habits in 1986. After 20.3 years of follow-up, 2,321 incident breast cancer cases and 1,665 subcohort members were eligible for multivariate case-cohort analyses.

RESULTS

Total nut intake was significantly inversely related to ER negative (ER -) breast cancer risk, with HR 0.55 (95% CI 0.33-0.93) for those consuming at least 10 g nuts/day versus non-consumers (p trend = 0.025). There were no significant inverse associations with ER + or total breast cancer. While there was no variation between PR subtypes, the ER-PR- subtype was also significantly inversely associated with nut intake, with HR 0.53 (95% CI 0.29-0.99), p trend = 0.037. Intake of peanuts and tree nuts separately was also inversely related to ER - breast cancer subtypes, while no associations were found with peanut butter intake.

CONCLUSIONS

Our findings suggest an inverse association between nut intake and ER - breast cancer, and no association with total or hormone receptor-positive subtypes.

Peanut consumption associated with a reduced risk of esophageal squamous cell carcinoma: A case-control study in a high-risk area in China

Background

Esophageal cancer (EC) is ranked as the top 10th malignancy in China; however, an association between peanut consumption and EC risk has not yet been identified. This study explored the protective effects of peanut consumption against the risk of developing esophageal squamous cell carcinoma (ESCC) in a high‐risk area.

Methods

A case–control design was applied, with frequency matching by age and gender. A logistic regression model was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Two hundred and twenty‐two cases and 222 controls were recruited from Yanting County from 2011 to 2012.

Results

Peanut consumption 1–3 times per week reduced cancer risk by 38% (OR 0.62, 95% CI 0.34–1.13), while consumption ≥ 4 times per week reduced the risk by 70% (OR 0.31, 95% CI 0.16–0.59). A significant association was observed among individuals with negative family EC history (OR 0.25, 95% CI 0.12–0.49).

Conclusion

Peanut consumption may act as a protector against the occurrence of ESCC in high‐risk areas, thus production and consumption should be promoted in high‐risk areas in order to reduce the ESCC burden.

Dietary Profiles of First-Generation South Asian Indian Adolescents in the United States

This study aimed to describe the dietary profile and health characteristics of first-generation South Asian Indian (SAI) adolescents in the United States because SAIs have a high prevalence of cardiovascular disease and diabetes, and dietary risk factors for those diseases begin in youth. A descriptive cross-sectional design was used to examine age, gender, usual dietary intake, body composition, blood pressure, blood glucose, and length of residency among 56 first-generation, urban SAI adolescents. Intake of saturated fat exceeded recommendations for all participants, and potassium, magnesium, calcium, vitamin D, and fiber intakes were insufficient in nearly all. Sodium intake exceeded recommendations for most males. Cholesterol intake and sweets consumption was lower among those who lived in the U.S. longer. There were no associations of dietary patterns with health characteristics. Dietary patterns that may increase future disease risk included high saturated fats and low potassium, magnesium, calcium, vitamin D, and fiber.

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.

Intakes of fat and micronutrients between ages 13 and 18 years and the incidence of proliferative benign breast disease

PURPOSE

Dietary exposures during adolescence may exert important effects on breast development and future breast cancer risk. This study evaluated the associations between high school intakes of fat and micronutrients and the incidence of proliferative benign breast disease (BBD), a marker of increased breast cancer risk.

METHODS

29,480 women (mean age 43.3 years, range 33.6-52.9) completed a high school food frequency questionnaire in 1998 in the Nurses' Health Study II. Between 1991 and 2001, 682 women (follow-up time: 259,828 person-years) were diagnosed with proliferative BBD whose biopsy slides were reviewed and confirmed by the study pathologists.

RESULTS

In multivariate Cox proportional hazards models, high school intakes of total fat and types of fat were not associated with proliferative BBD. Women in the highest quintile of total retinol activity equivalents (RAEs), which incorporate retinol, α- and β-carotene, and β-cryptoxanthin intakes, had a 17 % lower risk of proliferative BBD than those in the lowest quintile [multivariate hazard ratio (HR) 95 % CI 0.83 (0.64, 1.07), p trend = 0.01]; however, additional adjustment for high school dietary factors (vitamin D, nuts, and fiber) rendered the association nonsignificant [0.99 (0.73, 1.34), p trend = 0.32]. Results were similar with additional adjustment for adult RAE intake. Intakes of vitamin E and individual carotenoids were not associated with proliferative BBD, although an inverse association cannot be ruled out.

CONCLUSIONS

In this study, adolescent fat and micronutrient intakes were not associated with risk of proliferative BBD.

Adolescent meat intake and breast cancer risk

The breast is particularly vulnerable to carcinogenic influences during adolescence due to rapid proliferation of mammary cells and lack of terminal differentiation. We investigated consumption of adolescent red meat and other protein sources in relation to breast cancer risk in the Nurses' Health Study II cohort. We followed prospectively 44,231 women aged 33-52 years who, in 1998, completed a detailed questionnaire about diet during adolescence. Relative risks (RR) and 95% confidence intervals (95%CI) were estimated using Cox proportional hazard regression. We documented 1132 breast cancer cases during 13-year follow-up. In multivariable Cox regression models with major breast cancer risk factors adjustment, greater consumption of total red meat in adolescence was significantly associated with higher premenopausal breast cancer risk (highest vs. lowest quintiles, RR, 1.43; 95%CI, 1.05-1.94; Ptrend  = 0.007), but not postmenopausal breast cancer. Adolescent intake of poultry was associated with lower risk of breast cancer overall (RR, 0.76; 95%CI, 0.60-0.97; for each serving/day). Adolescent intakes of iron, heme iron, fish, eggs, legumes and nuts were not associated with breast cancer. Replacement of one serving/day of total red meat with one serving of combination of poultry, fish, legumes, and nuts was associated with a 15% lower risk of breast cancer overall (RR, 0.85; 95%CI, 0.74-0.96) and a 23% lower risk of premenopausal breast cancer (RR, 0.77; 95%CI, 0.64-0.92). In conclusion, higher consumption of red meat during adolescence was associated with premenopausal breast cancer. Substituting other dietary protein sources for red meat in adolescent diet may decrease premenopausal breast cancer risk.

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.

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.

Adolescent carotenoid intake and benign breast disease

BACKGROUND

Carotenoids may reduce risk of benign breast disease (BBD), an independent risk factor for breast cancer, through antioxidative or antiproliferative mechanisms. Exposure to carotenoids may be most important during adolescence when breast tissue is still developing. We examined adolescent carotenoid intake in relation to BBD in young women.

METHODS

In 6593 adolescent girls in the prospective Growing Up Today Study cohort, intakes of α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, and lycopene were assessed by using the means from food-frequency questionnaires in 1996, 1997, and 1998. Girls reported biopsy-confirmed BBD on questionnaires in 2005, 2007, and 2010 (n = 122). We conducted logistic regression of energy-adjusted carotenoid intakes in relation to BBD, adjusted for age, family history of breast cancer or BBD, age at menarche, nulliparity, alcohol intake, BMI, and physical activity.

RESULTS

Mean (SD) age at baseline was 12.0 (1.6) years. β-Carotene intake was inversely associated with BBD; comparing the highest to lowest quartile, the multivariate-adjusted odds ratio was 0.58 (95% confidence interval: 0.34-1.00; P-trend = .03). α-Carotene and lutein/zeaxanthin were also inversely associated with BBD, but the associations were not statistically significant.

CONCLUSIONS

Adolescent carotenoid intake may be associated with lower BBD risk; these findings warrant further study.

Adolescent dietary fiber, vegetable fat, vegetable protein, and nut intakes and breast cancer risk

The importance of early-life exposures in breast cancer development is increasingly recognized. However, limited research has evaluated the relationship between adolescent diet and subsequent risk of breast cancer and reported inconsistent results. This population-based case-control study investigated the associations of dietary fiber, vegetable protein, vegetable fat, and nuts consumed during adolescence with adult breast cancer risk. Women, ages 25-74 years, who were diagnosed with first primary breast cancer between 2002 and 2003, were identified using the Ontario Cancer Registry. Controls were identified through random-digit dialing and age-frequency matched to cases. Diet at ages 10-15 was assessed with a 55-item food frequency questionnaire among 2,865 cases and 3,299 controls. Logistic regression was performed to estimate odds ratios (ORs) and 95 % confidence intervals (CIs). Inverse associations were found between intakes of dietary fiber, vegetable protein, vegetable fat, and nuts during adolescence and breast cancer risk, which persisted after controlling for adult intakes. The ORs (95 % CI) for the highest versus the lowest quintile of intake were 0.66 (0.55-0.78; P trend < 0.0001) for fiber, 0.80 (0.68-0.95; P trend = 0.01) for vegetable protein, 0.74 (0.63-0.87; P trend = 0.002) for vegetable fat, and 0.76 (0.61-0.95 for ≥1 serving/day vs. <1 serving/month intake; P trend = 0.04) for nuts. The reduced risk for adolescent intakes of fiber, vegetable protein, and nuts was largely limited to postmenopausal women (P interaction ≤ 0.05). Dietary fiber, vegetable protein, vegetable fat, and nuts consumed during adolescence were associated with reduced breast cancer risk.

Adolescent dietary fiber, vegetable fat, vegetable protein, and nut intakes and breast cancer risk

The importance of early-life exposures in breast cancer development is increasingly recognized. However, limited research has evaluated the relationship between adolescent diet and subsequent risk of breast cancer and reported inconsistent results. This population-based case-control study investigated the associations of dietary fiber, vegetable protein, vegetable fat, and nuts consumed during adolescence with adult breast cancer risk. Women, ages 25-74 years, who were diagnosed with first primary breast cancer between 2002 and 2003, were identified using the Ontario Cancer Registry. Controls were identified through random-digit dialing and age-frequency matched to cases. Diet at ages 10-15 was assessed with a 55-item food frequency questionnaire among 2,865 cases and 3,299 controls. Logistic regression was performed to estimate odds ratios (ORs) and 95 % confidence intervals (CIs). Inverse associations were found between intakes of dietary fiber, vegetable protein, vegetable fat, and nuts during adolescence and breast cancer risk, which persisted after controlling for adult intakes. The ORs (95 % CI) for the highest versus the lowest quintile of intake were 0.66 (0.55-0.78; P trend < 0.0001) for fiber, 0.80 (0.68-0.95; P trend = 0.01) for vegetable protein, 0.74 (0.63-0.87; P trend = 0.002) for vegetable fat, and 0.76 (0.61-0.95 for ≥1 serving/day vs. <1 serving/month intake; P trend = 0.04) for nuts. The reduced risk for adolescent intakes of fiber, vegetable protein, and nuts was largely limited to postmenopausal women (P interaction ≤ 0.05). Dietary fiber, vegetable protein, vegetable fat, and nuts consumed during adolescence were associated with reduced breast cancer risk.