Associations of intakes of total protein, protein from dairy sources, and dietary calcium with risks of colorectal, breast, and prostate cancer: a prospective analysis in UK Biobank

BACKGROUND

Evidence concerning intakes of protein or sources of dairy protein and risks of colorectal, breast, and prostate cancers is inconclusive.

METHODS

Using a subsample of UK Biobank participants who completed ≥2 (maximum of 5) 24-h dietary assessments, we estimated intakes of total protein, protein from total dairy products, milk, and cheese, and dietary calcium in 114,217 participants. Hazard ratios (HRs) and 95% confidence intervals (CI) were estimated using multivariable-adjusted Cox regression.

RESULTS

After a median of 9.4 years of follow-up, 1193 colorectal, 2024 female breast, and 2422 prostate cancer cases were identified. There were inverse associations of total dairy protein, protein from milk, and dietary calcium intakes with colorectal cancer incidence (HRQ4 vs Q1:0.80, 95% CI: 0.67-0.94; 0.79, 0.67-0.94; 0.71, 0.58-0.86, respectively). We also observed positive associations of milk protein and dietary calcium with prostate cancer risk (HRQ4 vs Q1:1.12, 1.00-1.26 and 1.16, 1.01-1.33, respectively). No significant associations were observed between intake of dairy protein and breast cancer risk. When insulin-like growth factor-I concentrations measured at recruitment were added to the multivariable-adjusted models, associations remained largely unchanged. Analyses were also similar when looking at total grams of dairy products, milk, and cheese.

CONCLUSION

Further research is needed to understand the mechanisms underlying the relationships of dairy products with cancer risk and the potential roles of dietary protein and calcium.

Risk of Cancer in Regular and Low Meat-Eaters, Fish-Eaters, and Vegetarians: A Prospective Analysis of UK Biobank Participants

Objectives

Vegetarians may have a lower risk of cancer overall; however, for specific cancer sites, the evidence is limited. We aimed to assess the associations of vegetarian and non-vegetarian diets with risks of all cancer, colorectal cancer, postmenopausal breast cancer, and prostate cancer, and to explore the role of potential mediators.

Methods

We conducted a prospective analysis of 472,377 UK Biobank participants who were free from cancer at recruitment. Participants were categorised into regular meat-eaters (n = 247,571), low meat-eaters (n = 205,385), fish-eaters (n = 10,696), and vegetarians (n = 8,685) based on dietary questions completed at recruitment. Multivariable-adjusted Cox regressions were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for all cancer incidence and separate cancer sites across diet groups.

Results

After an average follow-up of 11.4 years, 54,961 incident cancers were identified from health records, including 5,882 colorectal, 7,537 postmenopausal breast, and 9,501 prostate cancers. Compared with regular meat-eaters, being a low meat-eater, fish-eater, or vegetarian were all associated with a lower risk of all cancer (HR:0.98, 95% CI:0.96–1.00; 0.90, 0.84–0.96; 0.86, 0.80–0.93, respectively). Being a low meat-eater was associated with a lower risk of colorectal cancer in comparison to regular meat-eaters (0.91, 0.86–0.96). Vegetarian postmenopausal women had a lower risk of breast cancer (0.82, 0.68–0.99), which was attenuated and non-significant after adjusting for BMI (0.87, 0.72–1.05); in mediation analyses, BMI was found to possibly mediate the observed association. In men, being a fish-eater or a vegetarian was associated with a lower risk of prostate cancer (0.80, 0.65–0.99 and 0.69, 0.54–0.89, respectively).

Conclusions

The lower risk of colorectal cancer in low meat-eaters is consistent with previous evidence suggesting an adverse impact of higher meat intake. The lower risk of postmenopausal breast cancer in vegetarian women may be explained by their lower BMI. It is unclear if the other differences observed for all cancers and for prostate cancer reflect causal relationships or are due to residual confounding or differences in cancer detection.

Funding Sources

CRUK grant (C8221/A29017) and World Cancer Research Fund UK(2019/1953).

Adiposity and risk of prostate cancer death: a prospective analysis in UK Biobank and meta-analysis of published studies

BACKGROUND

The association of adiposity with prostate cancer specific mortality remains unclear. We examined how adiposity relates to fatal prostate cancer and described the cross-sectional associations of commonly used adiposity measurements with adiposity estimated by imaging in UK Biobank. We also conducted a dose-response meta-analysis to integrate the new data with existing prospective evidence.

METHODS

218,237 men from UK Biobank who were free from cancer at baseline were included. Body mass index (BMI), total body fat percentage (using bioimpedance), waist circumference (WC) and waist-to-hip ratio (WHR) were collected at recruitment. Risk of dying from prostate cancer (primary cause) by the different adiposity measurements was estimated using multivariable-adjusted Cox proportional hazards models. Results from this and other prospective cohort studies were combined in a dose-response meta-analysis.

RESULTS

In UK Biobank, 661 men died from prostate cancer over a mean follow-up of 11.6 years. In the subsample of participants with magnetic resonance imaging and dual-energy X-ray absorptiometry, BMI, body fat percentage and WC were strongly associated with imaging estimates of total and central adiposity (e.g. visceral fat, trunk fat). The hazard ratios (HR) for prostate cancer death were 1.07 (95% confidence interval = 0.97-1.17) per 5 kg/m2 higher BMI, 1.00 (0.94-1.08) per 5% increase in total body fat percentage, 1.06 (0.99-1.14) per 10 cm increase in WC and 1.07 (1.01-1.14) per 0.05 increase in WHR. Our meta-analyses of prospective studies included 19,633 prostate cancer deaths for BMI, 670 for body fat percentage, 3181 for WC and 1639 for WHR, and the combined HRs for dying from prostate cancer for the increments above were 1.10 (1.07-1.12), 1.03 (0.96-1.11), 1.07 (1.03-1.11), and 1.06 (1.01-1.10), respectively.

CONCLUSION

Overall, we found that men with higher total and central adiposity had similarly higher risks of prostate cancer death, which may be biologically driven and/or due to differences in detection. In either case, these findings support the benefit for men of maintaining a healthy body weight.

Risk of cancer in regular and low meat-eaters, fish-eaters, and vegetarians: a prospective analysis of UK Biobank participants

BACKGROUND

Following a vegetarian diet has become increasingly popular and some evidence suggests that being vegetarian may be associated with a lower risk of cancer overall. However, for specific cancer sites, the evidence is limited. Our aim was to assess the associations of vegetarian and non-vegetarian diets with risks of all cancer, colorectal cancer, postmenopausal breast cancer, and prostate cancer and to explore the role of potential mediators between these associations.

METHODS

We conducted a prospective analysis of 472,377 UK Biobank participants who were free from cancer at recruitment. Participants were categorised into regular meat-eaters (n = 247,571), low meat-eaters (n = 205,385), fish-eaters (n = 10,696), and vegetarians (n = 8685) based on dietary questions completed at recruitment. Multivariable-adjusted Cox regressions were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for all cancer incidence and separate cancer sites across diet groups.

RESULTS

After an average follow-up of 11.4 years, 54,961 incident cancers were identified, including 5882 colorectal, 7537 postmenopausal breast, and 9501 prostate cancers. Compared with regular meat-eaters, being a low meat-eater, fish-eater, or vegetarian were all associated with a lower risk of all cancer (HR: 0.98, 95% CI: 0.96-1.00; 0.90, 0.84-0.96; 0.86, 0.80-0.93, respectively). Being a low meat-eater was associated with a lower risk of colorectal cancer in comparison to regular meat-eaters (0.91, 0.86-0.96); however, there was heterogeneity in this association by sex (p = 0.007), with an inverse association across diet groups in men, but not in women. Vegetarian postmenopausal women had a lower risk of breast cancer (0.82, 0.68-0.99), which was attenuated and non-significant after adjusting for body mass index (BMI; 0.87, 0.72-1.05); in mediation analyses, BMI was found to possibly mediate the observed association. In men, being a fish-eater or a vegetarian was associated with a lower risk of prostate cancer (0.80, 0.65-0.99 and 0.69, 0.54-0.89, respectively).

CONCLUSION

The lower risk of colorectal cancer in low meat-eaters is consistent with previous evidence suggesting an adverse impact of meat intake. The lower risk of postmenopausal breast cancer in vegetarian women may be explained by their lower BMI. It is not clear whether the other differences observed for all cancers and for prostate cancer reflect any causal relationships or are due to other factors such as residual confounding or differences in cancer detection.

Dietary patterns and age at natural menopause: Evidence from the UK Women's Cohort Study

OBJECTIVES

To investigate prospective associations between dietary patterns and age of natural menopause.

STUDY DESIGN AND MAIN OUTCOME MEASURES

Menopausal status was reported at two time points 4  years apart in the UK Women's Cohort Study (UKWCS). Diet of participants was measured using a 217-item food frequency questionnaire at baseline. Principal component analysis (PCA) and reduced rank regression (RRR) were used to derive dietary patterns for 13,916 women. Cox proportional hazards regressions were used to estimate hazard ratios (HR) and 95 % confidence intervals (CIs) for each pattern in relation to age at natural menopause, adjusting for potential confounders.

RESULTS

Five patterns were identified from the PCA, labelled as: 'vegetables and legumes', 'animal proteins', 'fruits', 'fats and sweets' and 'low-fat products'. Three patterns were derived from RRR: 'sweets, pastries and puddings', 'low-fat dairy and meat', and 'red meat and processed meat'. Women who scored 1 standard deviation higher on the 'animal proteins' pattern were 6% more likely to experience a later natural menopause over the study (HR = 0.94, 95 % CI: 0.90-0.97) compared with those who scored lower. The 'red meat and processed meat' pattern similary predicted a 7% higher risk for a later menopause during the study (HR = 0.93, 95 % CI: 0.87-1.00) per 1 standard deviation.

CONCLUSIONS

Women whose diets are highly loaded with animal proteins, as well as red and processed meats, are more likely to have a later natural menopause.

Dietary intake and age at natural menopause: results from the UK Women's Cohort Study

BACKGROUND

Age at natural menopause is a matter of concern for women of reproductive age as both an early or late menopause may have implications for health outcomes.

METHODS

Study participants were women aged 40-65 years who had experienced a natural menopause from the UK Women's Cohort Study between baseline and first follow-up. Natural menopause was defined as the permanent cessation of menstrual periods for at least 12 consecutive months. A food frequency questionnaire was used to estimate diet at baseline. Reproductive history of participants was also recorded. Regression modelling, adjusting for confounders, was used to assess associations between diet and age at natural menopause.

RESULTS

During the 4-year follow-up period, 914 women experienced a natural menopause. A high intake of oily fish and fresh legumes were associated with delayed onset of natural menopause by 3.3 years per portion/day (99% CI 0.8 to 5.8) and 0.9 years per portion/day (99% CI 0.0 to 1.8), respectively. Refined pasta and rice was associated with earlier menopause (per portion/day: -1.5 years, 99% CI -2.8 to -0.2). A higher intake of vitamin B6 (per mg/day: 0.6 years, 99% CI 0.1 to 1.2) and zinc (per mg/day: 0.3 years, 99% CI -0.0 to 0.6) was also associated with later age at menopause. Stratification by age at baseline led to attenuated results.

CONCLUSION

Our results suggest that some food groups (oily fish, fresh legumes, refined pasta and rice) and specific nutrients are individually predictive of age at natural menopause.

Healthy Diet and Nutrition Education Program among Women of Reproductive Age: A Necessity of Multilevel Strategies or Community Responsibility

BACKGROUND

Reproductive years represent a major proportion of women‟s life. This review focuses on recommended nutritional considerations, physical activity pattern as well as the effect of nutrition education (NE) on behavior modification and health outcomes of women of reproductive age using either single-level, multiple-level or community-level interventions.

METHODS

For this narrative review, numerous searches were conducted on databases of PubMed, Science Direct and Google Scholar search engine using the keywords women, reproductive age, NE, interventions, community-based.

RESULTS

Even though single intervention is effective, multiple intervention programmes in addition to behavior modification components are even more successful in terms of modified behaviors and health outcomes. Moreover, community based interventions using multilevel strategies are further useful for improved health outcomes and behavior modification.

CONCLUSION

NE programmes have been effective in positive behavior modification measured in terms of eating pattern and health quality. Thus, it is recommended that health professionals use multiple intervention strategies at community level to ensure improved outcomes. Political support is also required to create culturally sensitive methods of delivering nutritional programmes. Finally, as policy is dependent on program cost, nutritional programmes need to combine methods of cost analysis to show cost effectiveness of supplying adequate nutrition for women throughout the lifecycle.