Higher dietary acid load is not associated with risk of breast cancer in Iranian women

The association of diet-dependent acid load with colorectal cancer risk: a case-control study in Korea

Acid-base disequilibrium is a contributor to cancer development because it affects molecular activities such as insulin-like growth factor 1 levels and adiponectin production. However, evidence of an association of diet-induced acid-base imbalance with colorectal cancer (CRC) is limited. We examined whether colorectal carcinogenesis is attributable to a diet with a high acid load. We recruited a total of 923 CRC cases and 1846 controls at the National Cancer Center in Korea for inclusion in a case-control study. We collected information on nutrient intake and specific clinical parameters of CRC by using a semiquantitative FFQ and medical records, respectively. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were used to estimate diet-dependent acid load. We used an unconditional logistic regression model to analyse the association. Dietary acid load scores had a positive association with the odds of CRC (OR = 2·31 (95 % CI 1·79, 2·99) and OR = 2·14 (95 % CI 1·66, 2·76) for PRAL and NEAP, respectively, Pfor trend < 0·001). A stronger positive association was observed for females (OR = 3·09, 95 % CI 1·93, 4·94) than for males (OR = 1·71, 95 % CI 1·27, 2·31). Furthermore, acidogenic diets appeared to affect rectal cancer more strongly than colon cancer in females. Our study contributes to reinforcing epidemiological evidence regarding a detrimental effect of acidogenic diets on colorectal carcinogenesis. Thus, it is important to pay attention to the balance of acidogenic (e.g. poultry and red meat) and alkalinogenic foods (e.g. fruits and vegetables) in CRC prevention, especially for females.

Breast cancer risk factors in Iranian women: a systematic review and meta-analysis of matched case-control studies

BACKGROUND

Identifying breast cancer risk factors is a critical component of preventative strategies for this disease. This study aims to identify modifiable and non-modifiable risk factors of breast cancer in Iranian women.

METHODS

We used international databases (PubMed/Medline, Scopus, Web of Knowledge, and Embase) and national databases (SID, Magiran, and ISC) to retrieve relevant studies until November 13, 2022. The odds ratio (OR) with a 95% confidence interval using the random-effect model was used to estimate the pooled effect. The publication bias was assessed by the Egger and Begg test. A sensitivity analysis was conducted to evaluate the effect of each included study on the final measurement.

RESULTS

Of the 30,351 retrieved articles, 24 matched case-control records were included with 12,460 participants (5675 newly diagnosed cases of breast cancer and 6785 control). This meta-analysis showed that of the known modifiable risk factors for breast cancer, obesity (vs normal weight) had the highest risk (OR = 2.17, 95% CI 1.47 to 3.21; I² = 85.7) followed by age at marriage (25-29 vs < 18 years old) (OR = 2.00, 95% CI 1.53 to 2.61; I² = 0), second-hand smoking (OR = 1.86, 95% CI 1.58 to 2.19; I² = 0), smoking (OR = 1.83, 95% CI 1.41 to 2.38; I² = 18.9), abortion history (OR = 1.44, 95% CI 1.02 to 2.05; I² = 66.3), oral contraceptive use (OR = 1.35, 95% CI 1.11 to 1.63; I² = 74.1), age at marriage (18-24 vs < 18 years old) (OR: 1.22, 95% CI 1.02 to 1.47; I² = 0). Of non-modifiable risk factors, history of radiation exposure (OR = 3.48, 95% CI 2.17 to 5.59; I² = 0), family history of breast cancer (OR = 2.47, 95% CI 1.83 to 3.33; I² = 73), and age at menarche (12-13 vs ≥ 14 years old) (OR = 1.67, 95% CI 1.31-2.13; I² = 25.4) significantly increased the risk of breast cancer.

CONCLUSIONS

Since most risk factors related to breast cancer incidence are modifiable, promoting healthy lifestyles can play an influential role in preventing breast cancer. In women with younger menarche age, a family history of breast cancer, or a history of radiation exposure, screening at short intervals is recommended.

Association between dietary acid load and cancer risk and prognosis: An updated systematic review and meta-analysis of observational studies

Epidemiological studies have suggested that dietary acid load (DAL) might be related to the risk and prognosis of cancer, whereas the evidence is contentious. Several high-quality observational studies have been published following a prior systematic review with only one study included. Consequently, we conducted an updated systematic review and meta-analysis to comprehensively investigate the relationship between DAL and cancer risk and prognosis. A systematic literature search was conducted in the PubMed, Embase, and Web of Science databases from inception to 26 October 2021. Summary relative risks (RRs) with 95% CIs were calculated using a random-effects model. Publication bias, subgroup, meta-regression, and sensitivity analyses were also conducted. Ten observational studies (six cohorts and four case–control studies) with 227,253 participants were included in this systematic review and meta-analysis. The summary RRs revealed a statistically significant associations between DAL and cancer risk (RR = 1.58, 95% CI = 1.23–2.05, I² = 71.9%, n = 7) and prognosis (RR = 1.53, 95% CI = 1.10–2.13, I² = 77.1%, n = 3). No evidence of publication bias was observed in the current analysis. Positive associations were observed in most subgroup analyses stratified by predefined factors, including region, study design, study quality, study population, participants’ gender, age of participants, cancer type, DAL assessment indicator, and adjustment of potential confounding parameters. No evidence of heterogeneity between subgroups was indicated by meta-regression analyses. The high DAL might be associated with an increased risk of cancer, as well as a poor prognosis of cancer. More high-quality prospective studies are warranted to further determine the associations between DAL and risk and prognosis for specific cancers.

Association of High Dietary Acid Load With the Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Objective

This study aimed to determine the relationship between the high dietary acid load (DAL) and the risk of cancer.

Methods

Five databases of PubMed, Web of Sciences, Scopus, Cochrane Library, and Google Scholar was searched to elicit original studies on humans, up to June 2021. Quality of the articles, risk of bias, and heterogeneity were assessed. A random-effects meta-analysis model was applied to estimate pooled effect size with a 95% confidence interval. Sensitivity analysis was performed using a fixed-effects model. Subgroup analyses were carried out based on gender, age, type of cancer, and type of DAL assessment indicator.

Results

Seventeen effect sizes from 10 articles were included in the analysis. Overall, individuals with the highest DAL were associated with a 66% increased risk of cancer compared to those with the lowest DAL (p < 0.001]. The risk of cancer increased 41% (p < 0.001) and 53% (p = 0.03) by high PRAL and NEAP, respectively. High DAL was associated with 32% (p < 0.001) and 79% (p < 0.001) increased risk of breast and colorectal cancers, respectively. High DAL was associated with 32% (p = 0.001) and 76% (p = 0.007) increased risk of cancer incident in women and men, respectively. The risk of cancer incident increased 35% (p < 0.001) and 49% (p < 0.001) at age ≤ and > of 50, respectively.

Conclusion

High DAL may be associated with a higher risk of cancer incidence not only in the whole studied population but also across cancer types, both genders, both DAL assessment indicators, and also among both high- and low-risk age groups for cancer.

Dietary Acid Load, Serum Polychlorinated Biphenyl Levels, and Mortality Following Breast Cancer in the Long Island Breast Cancer Study Project

Dietary acid load (DAL) may be associated with all-cause mortality (ACM) and breast cancer-specific mortality (BCM), and these associations may be modified by serum polychlorinated biphenyl (PCB) levels. Participants included 519 women diagnosed with first primary in situ or invasive breast cancer in 1996/1997 with available lipid-corrected PCB data. After a median of 17 years, there were 217 deaths (73 BCM). Potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores calculated from a baseline food frequency questionnaire estimated DAL. Cox regression estimated covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between PRAL and NEAP with mortality. We evaluated effect measure modification by total serum PCB levels (>median vs. ≤median). PRAL quartile 4 versus quartile 1 was associated with an ACM HR of 1.31 (95%CI = 0.90-1.92). In the upper median of PCBs, ACM HRs were 1.43 (95%CI = 0.96-2.11) and 1.40 (95%CI = 0.94-2.07) for PRAL and NEAP upper medians, respectively. In the lower median of PCBs, the upper median of NEAP was inversely associated with BCM (HR = 0.40, 95%CI = 0.19-0.85). DAL may be associated with increased risk of all-cause mortality following breast cancer among women with high total serum PCB levels, but inversely associated with breast cancer mortality among women with low PCB levels.

Higher Fruits and Vegetables Consumption Is not Associated with Risk of Breast Cancer in Iranian Women

We aimed to investigate the association of fruits and vegetables (FVs) and their all subgroups intakes with breast cancer (BC) risk in Iranian women.

The present case-control study conducted on 150 age-matched women with newly diagnosed BC and apparently healthy controls. Anthropometric measures were collected and eventually, the mean intakes of total FVs and each subgroup were obtained from a validated 147-item food frequency questionnaire. Multivariate regression analysis was used to estimate odds ratios (OR) with 95% confidence intervals (CI).

Our findings revealed that the intake of only dark yellow vegetable was significantly higher in BC patients (P = 0.03) after controlling for covariates. OR of BC across tertiles of FVs intake, showed that there was not any statistical association of total FVs (OR: 1.83, CI: 0.54-6.24, P-trend = 0.3) and their subgroups intakes with BC risk. Except for berry fruits intake which was adversely associated with BC risk (OR: 0.36, CI: 0.09-1.37, P-trend = 0.02).

Our findings did not support the hypothesis that higher total FVs and their subgroups intakes reduce BC risk and suggested that only higher berry fruits intake may have an association with lower BC risk.

Higher dietary acid load is not associated with risk of breast cancer in Iranian women

BACKGROUND

Dietary acid load (DAL) may play a key role in certain cancers, including breast cancer (BC); however, evidence showing a causal relationship is lacking.

AIM

We examined the relationship between DAL, assessed with both the potential renal acid load (PRAL) and the net endogenous acid production (NEAP) scores, and BC risk.

METHODS

We identified 150 women who had a diagnosis of BC recently and 150 age-matched apparently healthy controls. Data from dietary intake and anthropometric measures were collected from participants and eventually, PRAL and NEAP scores were obtained from nutrient intakes. Multivariate odds ratios (OR) with 95% confidence intervals (CI) were used to evaluate the relationship of BC risk with PRAL and NEAP scores.

RESULTS

The odds ratios (OR) of BC according to tertiles of PRAL and NEAP scores by multivariate logistic regression models revealed that both PRAL (P-trend = 0.8) and NEAP (P-trend = 0.1) scores were not significantly associated with BC risk. After controlling confounders, multiple logistic regressions still remained non-significant which indicated no significant associations between PRAL (P-trend = 0.9), NEAP (P-trend = 0.4) scores and risk of BC.

CONCLUSION

The results of our study suggested that there is no significant relationship between DAL and BC incidence among Iranian women.