Dietary acid load and mortality from all causes, CVD and cancer: results from the Golestan Cohort Study.

Given the limited studies and controversial results on association between dietary acid load and mortality from CVD and cancers, we aimed to investigate this association in a large population cohort study in Middle East, with a wide range of dietary acid load. The study was conducted on the platform of the Golestan Cohort Study (GCS), which enrolled 50 045 participants in 2004-2008. Dietary intake was assessed using a validated FFQ. Dietary potential renal acid load (PRAL) score was calculated from nutrient intake. Death and its causes were identified and confirmed by two or three physicians. Cox proportional hazards regression was used to estimate hazard ratio (HR) and 95 % CI for total and cause-specific mortalities. Then, the associations were modelled using restricted cubic splines. PRAL range was -57·36 to +53·81 mEq/d for men and -76·70 to +49·08 for women. During 555 142 person-years of follow-up, we documented 6830 deaths, including 3070 cardiovascular deaths, 1502 cancer deaths and 2258 deaths from other causes. For overall deaths, in final model after adjustment for confounders, participants in the first and fifth quintiles of PRAL had a higher risk of mortality compared with the second quintile of PRAL (HR: 1·08; 95 % CI1·01, 1·16 and HR: 1·07; 95 % CI 1·01, 1·15, respectively); Pfor trend < 0·05). Participants in the first and fifth quintiles of PRAL had a 12 % higher risk of CVD mortality compared with the Q2 of PRAL (HR: 1·12; 95 % CI 1·01-1·25 and HR: 1·12; 95 % CI 1·01, 1·26, respectively; Pfor trend < 0·05). We found that all-cause and CVD mortality rates were higher in the lowest and highest PRAL values, in an approximately U-shaped relation (P-values for the overall association and the non-linear association of energy-adjusted PRAL with total mortality were < 0·001 and < 0·001, and with CVD mortality were 0·008 and 0·003, respectively). Our results highlight unfavourable associations of high acidity and alkalinity of diet with the increased total and CVD mortality risk. It may be important to consider a balanced acid-base diet as a protective strategy to prevent pre-mature death, especially from CVD.

Dietary quality using four dietary indices and lung cancer risk: the Golestan Cohort Study (GCS).

PURPOSE: The lung cancer incidence in Iran has increased almost ten times over the past three decades. In addition to the known causes such as smoking and certain occupational exposure, dietary quality has been suggested to play a role in lung cancer. We aim to explore the association between dietary pattern and lung cancer risk among a Middle East population. METHODS: Data came from Golestan Cohort Study which included 48,421 participants with 136 lung cancer cases diagnosed during a median follow-up of 12 years. Multivariable Cox proportional hazards regression models were used to calculate the HRs and 95% CI of lung cancer risk by tertile of the four dietary index scores-the Health Eating Index (HEI)-2015, the Alternative Health Eating Index (AHEI)-2010, the Alternative Mediterranean Diet (AMED), and the Dietary Approach to Stop Hypertension (DASH)-Fung. RESULTS: A higher DASH-Fung score was inversely associated with risk of lung cancer after adjusting for potential confounders (tertile three vs. tertile one: HR = 0.59 (0.38-0.93); p for trend = 0.07), and pinteraction with smoking was 0.46. Similar findings were observed among current smokers with the HEI-2015 score (tertile three vs. tertile one: HR = 0.22 (0.08-0.60): p for trend < 0.01), and pinteraction between smoking and the HEI-2015 score was 0.03. CONCLUSION: In the GCS, consuming a diet more closely aligned with the DASH diet was associated with a reduced risk of lung cancer, which appeared to be independent of smoking status. There was also an inverse link between the HEI-2015 score and lung cancer risk among current smokers. Our finding is particularly important for the Middle East population, as diet may play an important role in cancer prevention and overall health.

Nut consumption and the risk of oesophageal squamous cell carcinoma in the Golestan Cohort Study.

BACKGROUND: Nut consumption has been inversely associated with gastric cancer incidence in US-based studies, but not with oesophageal cancer. However, there is aetiologic heterogeneity, among oesophageal squamous cell carcinoma (ESCC) cases in low-risk vs. high-risk populations. The objective of this study was to evaluate the association between nut consumption and risk of ESCC in a high-risk population. METHODS: The Golestan Cohort Study enroled 50,045 participants in Northeastern Iran, between 2004 and 2008. Intake of peanuts, walnuts and mixed nuts (including seeds) were assessed using a validated food frequency questionnaire at baseline. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals for subsequent ESCC adjusted for potential confounders. Non-consumers of nuts were used as the reference category and the consumers were categorised into tertiles. RESULTS: We accrued 280 incident ESCC cases during 337,983 person-years of follow up. Individuals in the highest tertiles of total nut consumption, and mixed nut consumption were significantly associated with lower risk of developing ESCC compared to non-consumers (HR = 0.60, 95% CI = 0.39-0.93, p-trend = 0.02, and HR = 0.52, 95% CI = 0.32-0.84, p trend = 0.002, respectively). CONCLUSIONS: We found a statistically significant inverse association between total nut consumption and the risk of ESCC in this high-risk population.

Nut consumption and total and cause-specific mortality: results from the Golestan Cohort Study.

Background: A number of prospective studies have observed inverse associations between nut consumption and chronic diseases. However, these studies have predominantly been conducted in Western countries, where nut consumption tends to be more common among individuals with healthier lifestyles. It is important to examine the association in other parts of the world, and particularly among populations with different patterns of disease, socioeconomic status, lifestyles and disease risk factors. Our objective was to examine the association between nut consumption and mortality in a population whose nut consumption does not track with a healthy lifestyle. Methods: We examined the association between nut consumption and all-cause and cause-specific mortality in the 50 045 participants of the Golestan Cohort Study. Participants were aged 40 and older at baseline in 2004, and have been actively followed since that time. Dietary data were collected using a validated semi-quantitative food frequency questionnaire that was administered at baseline. Results: During 349 677 person-years of follow-up, 3981 cohort participants died, including 1732 women and 2249 men. Nut consumption was associated inversely with all-cause mortality. The pooled multivariate adjusted hazard ratios for death among participants who ate nuts, as compared with those who did not, were 0.89 [95% confidence interval (CI), 0.82-0.95] for the consumption of less than one serving of nuts per week, 0.75 (95% CI, 0.67-0.85) for one to less than three servings per week and 0.71 (95% CI, 0.58-0.86) for three or more servings per week ( P < 0.001 for trend). Among specific causes, significant inverse associations were observed between nut consumption and deaths due to cardiovascular disease, all cancers and gastrointestinal cancers. Conclusions: This study provides evidence for an inverse association between nut consumption and mortality in a developing country, where nut consumption does not track with a healthy lifestyle. Further work is needed to establish the underlying mechanisms responsible for this association.

Heart Disease Is Associated With Anthropometric Indices and Change in Body Size Perception Over the Life Course: The Golestan Cohort Study.

BACKGROUND: Cardiovascular disease and obesity are now becoming leading causes of morbidity and mortality in low- and middle-income countries. OBJECTIVES: We investigated the relationship between prevalent heart disease (HD) and current anthropometric indices and body size perception over time from adolescence to adulthood in Iran. METHODS: We present a cross-sectional analysis of baseline data from a prospective study of adults in Golestan Province, Iran. Demographics, cardiac history, and current anthropometric indices-body mass index, waist circumference, and waist to hip ratio-were recorded. Body size perception for ages 15 years, 30 years, and at the time of interview was assessed via pictograms. Associations of these factors and temporal change in perceived body size with HD were evaluated using multivariable logistic regression models. RESULTS: Complete data were available for 50,044 participants; 6.1% of which reported having HD. Higher body mass index, waist circumference, and waist to hip ratio were associated with HD (p < 0.001). Men had a U-shaped relationship between HD and body size perception at younger ages. For change in body size perception, men and women demonstrated a U-shaped relationship with prevalent HD from adolescence to early adulthood, but a J-shaped pattern from early to late adulthood. CONCLUSIONS: HD was associated with anthropometric indices and change in body size perception over time for men and women in Iran. Due to the increasing prevalence of overweight and obesity in low- and middle-income countries, interventions focused on decreasing the cumulative burden of risk factors throughout the life course may be an important component of cardiovascular risk reduction.

Variation in PAH-related DNA adduct levels among non-smokers: the role of multiple genetic polymorphisms and nucleotide excision repair phenotype.

Polycyclic aromatic hydrocarbons (PAHs) likely play a role in many cancers even in never-smokers. We tried to find a model to explain the relationship between variation in PAH-related DNA adduct levels among people with similar exposures, multiple genetic polymorphisms in genes related to metabolic and repair pathways, and nucleotide excision repair (NER) capacity. In 111 randomly selected female never-smokers from the Golestan Cohort Study in Iran, we evaluated 21 SNPs in 14 genes related to xenobiotic metabolism and 12 SNPs in eight DNA repair genes. NER capacity was evaluated by a modified comet assay, and aromatic DNA adduct levels were measured in blood by32P-postlabeling. Multivariable regression models were compared by Akaike's information criterion (AIC). Aromatic DNA adduct levels ranged between 1.7 and 18.6 per 10(8) nucleotides (mean: 5.8 ± 3.1). DNA adduct level was significantly lower in homozygotes for NAT2 slow alleles and ERCC5 non-risk-allele genotype, and was higher in the MPO homozygote risk-allele genotype. The sum of risk alleles in these genes significantly correlated with the log-adduct level (r = 0.4, p < 0.001). Compared with the environmental model, adding Phase I SNPs and NER capacity provided the best fit, and could explain 17% more of the variation in adduct levels. NER capacity was affected by polymorphisms in the MTHFR and ERCC1 genes. Female non-smokers in this population had PAH-related DNA adduct levels three to four times higher than smokers and occupationally-exposed groups in previous studies, with large inter-individual variation which could best be explained by a combination of Phase I genes and NER capacity.

Vitamin deficiency in Golestan Province, northern Iran: a high-risk area for esophageal cancer.

OBJECTIVE: Dietary factors seem to play a major role in esophageal carcinogenesis in Golestan Province, a high-incidence area for esophageal cancer in northern Iran. The current study was conducted to evaluate previous reports on severe deficiency of vitamin intake in Golestan. METHODS: Using a food frequency questionnaire, food intake data were collected from 30,463 healthy participants in the Golestan Cohort Study. Intake of selected nutrients was compared with recommended daily allowance and lowest threshold intake values. RESULTS: Vitamin A intake in the majority of participants was lower than recommended values. The proportion of participants with intakes lower than lowest threshold intake was as follows: urban men, 20%; urban women, 31%; rural men, 48%; and rural women, 64%. The pattern of vitamin C deficiency was similar to that of vitamin A, however, vitamin C deficiency was less common. Daily intake of vitamin C lower than the LTI was as follows: urban men, 6%; urban women, 9%; rural men, 13%; and rural women, 19%. On the other hand, protein intake in the majority of the general population in Golestan was higher than recommended values. CONCLUSION: Severe deficiency in vitamin intake among women and rural dwellers may partly explain the high incidence of EC among inhabitants in rural areas and the male:female ratio that is approximately 1 in Golestan; while EC is much more common in men in many low-incidence areas.

Patterns of food and nutrient consumption in northern Iran, a high-risk area for esophageal cancer.

Our objectives were to investigate patterns of food and nutrient consumption in Golestan province, a high-incidence area for esophageal cancer (EC) in northern Iran. Twelve 24-h dietary recalls were administered during a 1-yr period to 131 healthy participants in a pilot cohort study. We compare here nutrient intake in Golestan with recommended daily allowances (RDAs) and lowest threshold intakes (LTIs). We also compare the intake of 27 food groups and nutrients among several population subgroups using mean values from the 12 recalls. Rural women had a very low level of vitamin intake, which was even lower than LTIs (P < 0.01). Daily intake of vitamins A and C was lower than LTI in 67% and 73% of rural women, respectively. Among rural men, the vitamin intakes were not significantly different from LTIs. Among urban women, the vitamin intakes were significantly lower than RDAs but were significantly higher than LTIs. Among urban men, the intakes were not significantly different from RDAs. Compared to urban dwellers, intake of most food groups and nutrients, including vitamins, was significantly lower among rural dwellers. In terms of vitamin intake, no significant difference was observed between Turkmen and non-Turkmen ethnics. The severe deficiency in vitamin intake among women and rural dwellers and marked differences in nutrient intake between rural and urban dwellers may contribute to the observed epidemiological pattern of EC in Golestan, with high incidence rates among women and people with low socioeconomic status and the highest incidence rate among rural women.