Long-term (24-year) recall reliability in cancer cases and controls using a 21-item food frequency questionnaire

The Association Between Dietary Intake of Sodium, Potassium, and Na:K Ratio with the Risk of NAFLD: A Case-Control Study Among Iranian Adults

Backgrounds

Dietary sodium (Na) and potassium (K) relationship with chronic disease has drawn more attention recently. Epidemiological studies reported controversial findings about high salt and Na diets with the risk of nonalcoholic fatty liver disease (NAFLD) and studies about the association between K and NAFLD are scare. Present study aimed to examine the associations between dietary intake of Na, K, and Na:K ratio with the risk of NAFLD.

Methods

We analyzed data from a case-control study of 225 patients with NAFLD cases and 450 controls. Dietary intake of Na and K measured using a validated 168 item food frequency questionnaire. Adjusted logistic regression models were used to report odds ratio (OR) 95% confidence interval (CI) of NAFLD across tertiles of Na, K, and Na:K ratio.

Results

The mean ± standard deviation of age and body mass index of participants (47% female) were 38.1 ± 8.8 years and 26.8 ± 4.3 Kg/m2. In the age- and sex-adjusted model, there was any significant association between Na, K, and Na: K ratio with the risk of NAFLD. In the final adjusted model, the OR (95%CI) of the highest vs the lowest tertiles of K, Na, and Na:K was 0.39 (0.19-0.80), 0.71 (0.40-1.25), and 1.10 (0.61-1.97), respectively.

Conclusion

The present study indicates that higher dietary K was related to lower odds of NAFLD; however, there was no association between dietary Na and Na: K ratio with odds of NAFLD.

Vegetarian Dietary Patterns and Cognitive Function among Older Adults: The Adventist Health Study-2

We explored effects on cognitive function of following plant-based vegetarian compared with non-vegetarian dietary patterns in otherwise healthy older community-dwelling members of the Adventist Health Study-2 cohort (n = 132). Cognition was assessed using a comprehensive neuropsychological battery; a principal components analysis derived processing speed, executive function, and memory/language factors. Mild memory impairment (MMI) (n = 26, 19.7%) was identified by memory tests. Vegetarians consumed (a) meats, fish, and dairy <1 time/month, (b) dairy ≥1 time/month and meats, and fish <1 time/month, or (c) fish ≥1 time/month, no limits on dairy, and meats <1 time/month. Dietary patterns were determined at baseline, for each decade, and at cognitive assessment; a diet stability score was calculated. Factor scores were not different between vegetarians and non-vegetarians, nor was dietary pattern associated with a lower odds of MMI. A more stable diet over the life course was associated with better memory/language [β = 0.021 SE(β) = 0.008; p = 0.01]. This exploratory study did not support differences in processing speed, executive function, or memory/language abilities between vegetarians and non-vegetarians but did suggest that a more stable dietary pattern which was characteristic of vegetarians was associated with better memory/language abilities.

Diet Quality Indices in the SUN Cohort: Observed Changes and Predictors of Changes in Scores Over a 10-Year Period

BACKGROUND

Dietary quality indices (DQI) are widely used in nutritional epidemiology. However, how they might change over time in a Mediterranean population is not well understood.

OBJECTIVE

To evaluate within-participant longitudinal changes in scores for nine a priori-defined DQIs: Fat Quality Index (FQI), Carbohydrate Quality Index (CQI), Pro-vegetarian Dietary Pattern (PVG), Mediterranean Diet Adherence Screener (MEDAS), Mediterranean Diet Score (MDS), Dietary Approaches to Stop Hypertension (DASH), Mediterranean-DASH Intervention for Neurodegenerative Delay Diet (MIND), Prime Diet Quality Score (PDQS) and Alternate Healthy Eating Index (AHEI-2010) in the "Seguimiento Universidad de Navarra" (SUN) cohort, a well-known Mediterranean cohort of university graduates, and to identify baseline predictors of improvement in MEDAS and AHEI-2010 after 10 years of follow-up.

DESIGN

In this longitudinal cohort study, DQI scores were calculated based on responses from a validated semiquantitative food-frequency questionnaire (FFQ).

PARTICIPANTS/SETTING

Spanish university graduates enrolled in the SUN cohort before March 2008, who completed the 10-year FFQ and reported total dietary intake at baseline and after 10 years of follow-up, included 2,244 men and 3,271 women, whose mean age at baseline was 36.3 years (standard deviation [SD], 10.7).

MAIN OUTCOME MEASURES

Main outcome measures were within-participant longitudinal changes for FQI, CQI, PVG, MEDAS, MDS, DASH, MIND, PDQS, and AHEI-2010.

STATISTICAL ANALYSES PERFORMED

Adjusted logistic regression models were used to evaluate within-participant longitudinal changes and to identify baseline predictors of improvements ≥10% in MEDAS and AHEI-2010 scores after 10 years of follow-up.

RESULTS

The comparison of the nine scores of DQI calculated at baseline and after 10 years of follow-up showed an improvement in all DQI scores except for PDQS. The greatest changes in DQIs were found for MEDAS (from 6.2 to 7.2, +22.9%) and MDS (from 4.3 to 4.4, +15.4%). The strongest predictors at baseline for ≥10% improvements in MEDAS or AHEI-2010 scores varied across indices. Being female, ≥35 years old, and more physically active at baseline were associated with improvement, whereas snacking between meals was associated with <10% improvements in both indices.

CONCLUSIONS

In this cohort, the changes in nine a priori-defined DQI scores suggested modest improvements in diet quality, in which MEDAS and MDS scores showed the largest improvements. Additional longitudinal studies, especially intervention trials with long follow-up, are warranted to establish the most appropriate DQIs to assess long-term changes in diet quality in adult populations.

Dietary measures among patients with coronary heart disease in Europe. ESC EORP Euroaspire V

OBJECTIVE

Assess the dietary recommendations provided to patients hospitalized for a coronary heart disease (CHD) event.

DESIGN

Cross-sectional, multicentre observational study (ESC EORP Euroaspire V).

METHODS

8261 participants (25.8% women, 9.3% aged<50 years) from 27 countries, 6 to 24 months after hospitalization for a CHD event were included. Participants were asked if they had been advised to reduce salt, fat or sugar intake, change type of fat consumed, and increase consumption of plant stanols/sterols, fruit & vegetables, fish and oily fish. Self-reported changes were recorded.

RESULTS

Advice to reduce energy intake, salt, fat and sugar was provided to 64.5% [range: 9.2-90.5], 73.2% [38.6-95.2], 77.3% [42.3-95.6] and 67.0% [39.4-93.3] of patients, respectively. Advice to change fat type, increase consumption of plant stanols/sterols, fruit & vegetables, fish and oily fish was provided to 68.3% [33.7-92.3], 36.7% [0.6-75.2], 73.2% [39.2-93.6], 66.5% [8.0-90.8] and 53.5% [3.7-83.3] of patients, respectively. Advices were more frequently provided to patients aged 50 to 69, with a high educational level, or obesity. One-eighth [0-55.0] of patients reported having consulted a dietician. Reductions in energy intake, salt, fat and sugar were reported by 57.7% [4.9-81.0], 69.9% [32.1-85.9], 71.8% [40.4-88.4] and 61.2% [29.0-84.0] of patients, respectively. Changes in fat type and increased consumption of plant stanols/sterols, fruit & vegetables, fish and oily fish were reported by 60.9% [4.9-81.0], 25.8% [0.6-54.1], 69.2% [27.7-88.4], 54.8% [4.0-80.1] and 40.4% [2.0-66.8] of patients, respectively.

CONCLUSION

Dietary advice is not systematically provided to patients with CHD, and considerable differences exist between European countries.

Association between inflammatory potential of diet and odds of gestational diabetes mellitus among Iranian women

Background: The possible relationship between diet-related inflammation and the risk of gestational diabetes mellitus (GDM) requires further investigation, especially in non-Western populations. We examined the association between dietary inflammatory index (DII) scores and GDM in a case-control study conducted in Iran. Methods: This study included 122 GDM cases and 266 controls hospitalized for acute non-neoplastic diseases. Cases were pregnant women aged 18-40 years, who visited major general hospitals in different regions of Tehran. Pregnant women were screened for gestational diabetes between the 24th and 28th week of gestation with a 50-g, 1-hour glucose challenge test (GCT). Cases were diagnosed positive for GDM. Controls were pregnant women who had normal GCT test. DII scores were computed from dietary intake assessed by a previously validated 147-item food frequency questionnaire. Logistic regression models adjusted age, gestational age, energy, exercise, BMI, smoking exposure, family history of diabetes, and history of multivitamin intake were used to estimate odds ratios (ORs) and 95% confidence intervals (CI). Results: Subjects with higher DII scores (i.e. indicating a more proinflammatory diet) had a higher odd of GDM with the DII being used as both a continuous (OR = 1.20; 95% CI = 0.94-1.54) and as categorical (ORtertile 3vs1 = 2.10; 95% CI = 1.02-4.34, p-trend = .03). Conclusions: These results indicate that a proinflammatory diet, as evidenced by higher DII scores, is associated with increased odds of GDM among Iranian women.

Increased Inflammatory Potential of Diet Is Associated with Increased Risk of Bladder Cancer in an Iranian Case-Control Study

Purpose: Various aspects of diet have been implicated to play a role in the etiology of bladder cancer. Studies examining this association have been conducted primarily in Western countries but none in Middle Eastern Countries. Method: We examined the association between the dietary inflammatory index (DII^®) and bladder cancer in an Iranian case-control study. A total of 56 incident cases with a mean age of 60 years and 109 controls with a mean age of 57 years, attending the same hospital as the cases during the same time period, were recruited. The DII is a literature-derived index developed to determine the inflammatory potential of diet and was computed using a validated food frequency questionnaire. Logistic regression was used to estimate odds ratios, with DII fit as continuous and as a dichotomous variable. Results: Multivariate analyses revealed that subjects with higher DII score (>-0.12) are at higher risk of bladder cancer [odds ratio (OR) = 2.46; 95% CI = 1.12-5.41, P value = 0.02)] compared to subjects with lower DII scores (≤-0.12). Stratified results showed stronger association was among current/ex-smokers (OR_{DII (>-0.12/≤-0.12)} = 3.30; 95% CI = 1.07-10.16). Conclusion: These data suggest a pro-inflammatory diet may be a risk factor for bladder cancer among Iranians.

Diet-related inflammation and risk of prostate cancer in the California Men's Health Study

PURPOSE

The purpose of the study was to examine the relationship between proinflammatory diet and prostate cancer risk.

METHODS

Energy-adjusted Dietary Inflammatory Index (E-DII) scores were computed among 40,161 participants in the California Men's Health Study. Over 9.7 ± 3.8 years of follow-up, 2707 incident prostate cancer cases were diagnosed and categorized as low-, intermediate-, or high-risk, based on disease grade and stage. Accelerated failure-time models assessed time to diagnosis of prostate cancer. Cox proportional hazard models estimated hazard ratios (HR) and 95% confidence intervals (95% CI). Nonlinear effects of E-DII were modeled as third-order polynomials.

RESULTS

Time to prostate cancer diagnosis did not differ by E-DII quartile. The HR for high-risk prostate cancer increased in the third E-DII quartile (HRQ3 vs. Q1 = 1.36; 95% CI: 1.04-1.76), but not in the fourth (HRQ4 vs. Q1 = 0.99; 95% CI: 0.74-1.32, Ptrend = .74), suggesting a nonlinear dose-response. HR curves for prostate cancer increased exponentially above an E-DII threshold of ≈+3.0. HR curves for high-risk prostate cancer had a much steeper incline above an E-DII threshold of ≈+2.5. Curves were higher among Blacks and Whites relative to other races and among overweight or obese men. No relationship was observed between E-DII scores and intermediate- or low-risk disease.

CONCLUSIONS

Relationships between proinflammatory diet and prostate cancer risk may be nonlinear, with an increased risk above an E-DII threshold of ≈+2.5.

Dietary Inflammatory Index and Odds of Colorectal Cancer in a Case- Control Study from Iran

Background

In Iran, colorectal cancer (CRC) is the third and fourth leading cause of cancer incidence among men and women, respectively. Diet and inflammation have been suggested as important risk factors for CRC. We examined the association between dietary inflammatory index (DII) scores and CRC in a case-control study conducted in Iran.

Methods

This study included 71 CRC cases and 142 controls hospitalized for acute non-neoplastic diseases. DII scores were computed from dietary intake assessed by a previously validated food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI) adjusted for age, sex, education, energy intake, exercise, body mass index (BMI), smoking, family history of cancer, and history of aspirin, acetaminophen, and multivitamin use.

Results

Subjects with higher DII scores (i.e., indicating a more pro-inflammatory diet) had a higher odds of CRC with the DII being used as both a continuous variable (OR continuous = 2.20, 95% CI: 1.22-3.87) and as a categorical variable (OR tertile 3 vs tertile1 = 2.47, 95%CI: 1.10-5.55).

Conclusion

These results indicate that a pro-inflammatory diet is associated with increased odds of CRC in this Iranian population.

An association between diet quality index for Koreans (DQI-K) and total mortality in Health Examinees Gem (HEXA-G) study

BACKGROUND/OBJECTIVES

Diet quality scores or indices, based on dietary guidelines, are used to summarize dietary intake into a single numeric variable. The aim of this study was to examine the association between the modified diet quality index for Koreans (DQI-K) and mortality among Health Examinees-Gem (HEXA-G) study participants.

SUBJECTS/METHODS

The DQI-K was modified from the original diet quality index. A total of 134,547 participants (45,207 men and 89,340 women) from the HEXA-G study (2004 and 2013) were included. The DQI-K is based on eight components: 1) daily protein intake, 2) percent of energy from fat, 3) percent of energy from saturated fat, 4) daily cholesterol intake, 5) daily whole-grain intake, 6) daily fruit intake, 7) daily vegetable intake, and 8) daily sodium intake. The association between all-cause mortality and the DQI-K was examined using Cox proportional hazard regression models. Hazard ratios and confidence intervals were estimated after adjusting for age, gender, income, smoking status, alcohol drinking, body mass index, and total energy intake.

RESULTS

The total DQI-K score was calculated by summing the scores of the eight components (range 0–9). In the multivariable adjusted models, with good diet quality (score 0–4) as a reference, poor diet quality (score 5–9) was associated with an increased risk of all-cause mortality (hazard ratios = 1.23, 95% confidence intervals = 1.06–1.43). Moreover, a one-unit increase in DQI-K score resulted in a 6% higher mortality risk.

CONCLUSIONS

A poor diet quality DQI-K score was associated with an increased risk of mortality. The DQI-K in the present study may be used to assess the diet quality of Korean adults.

Alternative Healthy Eating Index 2010, Dietary Inflammatory Index and risk of mortality: results from the Whitehall II cohort study and meta-analysis of previous Dietary Inflammatory Index and mortality studies

We aimed to examine the association between the Alternative Healthy Eating Index updated in 2010 (AHEI-2010), the Dietary Inflammatory Index (DIITM) and risk of mortality in the Whitehall II study. We also conducted a meta-analysis on the DII-based results from previous studies to summarise the overall evidence. Data on dietary behaviour assessed by self-administered repeated FFQ and on mortality status were available for 7627 participants from the Whitehall II cohort. Cox proportional hazards regression models were performed to assess the association between cumulative average of AHEI-2010 and DII scores and mortality risk. During 22 years of follow-up, 1001 participants died (450 from cancer, 264 from CVD). Both AHEI-2010 (mean=48·7 (sd 10·0)) and DII (mean=0·37 (sd 1·41)) were associated with all-cause mortality. The fully adjusted hazard ratio (HR) per sd, were 0·82; 95 % CI 0·76, 0·88 for AHEI-2010 and 1·18; 95 % CI 1·08, 1·29 for DII. Significant associations were also observed with cardiovascular and cancer mortality risk. For DII, a meta-analysis (using fixed effects) from this and four previous studies showed a positive association of DII score with all-cause (HR=1·04; 95 % CI 1·03, 1·05, 28 891deaths), cardiovascular (HR=1·05; 95 % CI 1·03, 1·07, 10 424 deaths) and cancer mortality (HR=1·05; 95 % CI 1·03, 1·07, n 8269).The present study confirms the validity to assess overall diet through AHEI-2010 and DII in the Whitehall II cohort and highlights the importance of considering diet indices related to inflammation when evaluating all-cause, cardiovascular and cancer mortality risk.

Dietary inflammatory index and risk of renal cancer in the Iowa Women's Health Study

BACKGROUND

The association between inflammatory potential of diet and renal cancer risk has not been investigated.

METHODS

In this study, we explored the association between the dietary inflammatory index (DII) and risk of renal cancer in the Iowa Women's Health Study. From 1986 to 2011, 33,817 women initially recruited at 55-69 years of age were followed for incident renal cancers (n = 263). The DII was computed based on dietary intake assessed using a reproducible and valid 121-item food frequency questionnaire. Cox proportional hazards regression was used to estimate hazard ratios (HR) adjusting for age, body mass index, energy intake, smoking status, education, pack years of smoking, hypertension, and hormone replacement therapy.

RESULTS

Multivariable analyses revealed positive association between higher DII scores and renal cancer risk (HR for DII_continuous: 1.07 per unit increase in DII (corresponding to 10% change in the DII range in the current study); 95% CI 1.00, 1.15; HR for DII_tertile3vs1 = 1.52; 95% CI 1.09, 2.13). Stratified analyses produced slightly stronger associations between DII and renal cancer risk among women with BMI <30 kg/m² (HR_Tertile3vs1 = 1.57; 95% CI = 1.04, 2.36) and ever smokers (HR_tertile3vs1 = 2.35; 95% CI = 1.22, 4.55), although the corresponding interaction p values were not significant.

CONCLUSION

Pro-inflammatory diet, as indicated by higher DII scores, was associated with increased renal cancer risk.

Dietary inflammatory index and odds of colorectal cancer in a case-control study from Jordan

Dietary components that promote inflammation of the colon have been suggested to be risk factors in the development of colorectal cancer (CRC). The possible link between inflammatory potential of diet and CRC has been investigated in several developed or Western countries. Despite the fact that dietary choices in the Middle East differ markedly from those in the West, results have not been reported from any study conducted in a Middle-Eastern population. We examined the association between dietary inflammatory index (DII) scores and CRC in a case-control study conducted in Jordan. This study included 153 histopathologically confirmed CRC cases and 202 disease-free control subjects' frequency matched on age, sex, and occupation. Data were collected between January 2010 and December 2012, using interviewer-administered questionnaires. DII scores were computed from dietary data reported using a food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age, sex, education, physical activity, body mass index, smoking, and family history of CRC. Subjects with higher DII scores were at increased odds of CRC, with the DII being used both as a continuous variable (OR_continuous = 1.45, 95% CI: 1.13-1.85; 1-unit increase corresponding to ≈20% of its range in the current study) and as a categorical variable (OR_{tertile 3 vs tertile 1} = 2.13, 95%CI: 1.23-3.72). Our results, based on a Jordanian population, add to the growing literature indicating that a pro-inflammatory diet is associated with increased odds of CRC.

The Dietary Inflammatory Index Is Associated with Colorectal Cancer Risk in the Multiethnic Cohort

Background: Diet is known to influence systemic inflammation, a recognized risk factor for colorectal cancer (CRC). Studies in ethnically diverse populations that examine the association between dietary inflammatory potential and CRC incidence are limited.Objectives: We used the Dietary Inflammatory Index to clarify the relation between the inflammatory potential of diet and CRC incidence across racial/ethnic groups. We hypothesized that proinflammatory diets would be associated with an increased risk of CRC, and that these associations may differ across racial/ethnic groups.Methods: The Multiethnic Cohort (MEC) follows a prospective study design. It includes 190,963 white, African-American, native Hawaiian, Japanese-American, and Latino men and women aged 45-75 y at recruitment and followed over 20 y. Participants completed a food frequency questionnaire from which energy-adjusted Dietary Inflammatory Index (E-DII) scores were computed and categorized into quartiles. CRC incidence was documented through linkage to cancer registry programs. Cox proportional hazards regression was used to estimate HRs and 95% CIs, adjusting for known or expected CRC risk factors.Results: Among all participants, more-proinflammatory diets (highest quartile compared with lowest quartile) were associated with an increased risk of CRC (HR: 1.21; 95% CI: 1.11, 1.32). However, the effect size was larger for men (HR: 1.28; 95% CI: 1.13, 1.45) than for women (HR: 1.16; 95% CI: 1.02, 1.33), although the interaction term for sex was not statistically significant (P-interaction = 0.17). When stratified by race/ethnicity, the association was significantly different between groups for men (P-interaction = 0.01), although not for women (P-interaction = 0.20). Significant associations with HRs ranging from 2.33 to 1.04 were observed in white, Japanese-American, and Latino men, and native Hawaiian women.Conclusions: Overall, more-proinflammatory diets, as identified by the E-DII, were associated with increased CRC risk in MEC participants across racial/ethnic groups. This study adds to the evidence suggesting that diets with high proinflammatory potential may increase CRC risk.

Polycyclic aromatic hydrocarbons and postmenopausal breast cancer: An evaluation of effect measure modification by body mass index and weight change

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) have been linked to breast cancer in many, but not all, previous studies. PAHs are lipophilic and stored in fat tissue, which we hypothesized may result in constant low-dose exposure to these carcinogens. No previous studies have evaluated whether obesity modifies associations between multiple measures of PAHs and breast cancer incidence.

METHODS

This population-based study included 1,006 postmenopausal women with first primary in situ or invasive breast cancer and 990 age-frequency matched controls. To evaluate effect modification by obesity (adult body mass index (BMI, kg/m²) and weight change) on multiple PAH measures (the biomarker PAH-DNA adducts, and long-term sources active cigarette smoking, living with a smoking spouse, grilled/smoked meat intake, residential synthetic log burning, and vehicular traffic), interaction contrast ratios (ICRs) for the additive scale, and ratio of odds ratios (RORs) with log-likelihood ratio tests (LRT) for the multiplicative scale, were determined using unconditional logistic regression.

RESULTS

BMI modified the PAH-DNA adduct and postmenopausal breast cancer association on the additive (ICR: 0.49; 95% CI: 0.01, 0.96) and multiplicative (ROR: 1.56; 95% CI: 0.91, 2.68) scales. The odds ratio for detectable vs. non-detectable adducts was increased among women with BMI ≥25 (OR=1.34; 95% CI: 0.94, 1.92), but not in those with BMI <25 (OR=0.86; 95% CI: 0.57, 1.28) (LRT p=0.1). For most other PAH measures, the pattern of modification by BMI/weight gain was similar, but estimates were imprecise.

CONCLUSIONS

The association between PAH-DNA adducts and breast cancer incidence may be elevated among overweight/obese women.

Genetic polymorphisms of phase I metabolizing enzyme genes, their interaction with lifetime grilled and smoked meat intake, and breast cancer incidence

PURPOSE

To examine associations between 22 CYP single nucleotide polymorphisms (SNPs) and breast cancer incidence and their interactions with grilled-smoked meat intake, a source of polycyclic aromatic hydrocarbons.

METHODS

White women with first primary in situ or invasive breast cancer (n = 988) and frequency-matched controls (n = 1021) from a population-based study were interviewed to assess lifetime grilled-smoked meat intake. SNPs with minor allele frequencies of greater than 0.05 were selected because of their links to carcinogenesis. We used multivariable unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Breast cancer was inversely associated with CYP1A1 rs104C8943 AG + GG genotype (OR = 0.71, 95% CI = 0.50-0.99; vs. AA genotype) and positively associated with CYP1B1 rs10175338 TT genotype (OR = 1.59, 95% CI = 1.12-2.26; vs. GG genotype) and the CYP3A4 rs2242480 CT + TT genotype (OR = 1.25, 95% CI = 1.00-1.56; vs. CC genotype). The sum of the number of "at-risk" alleles for the CYP SNPs was positively associated with breast cancer incidence (4-6 "at-risk" alleles OR = 2.33, 95% CI = 1.37-3.99 vs. 0-1 alleles; P_Trend < .01). We observed multiplicative and additive interactions (P < .05) between grilled-smoked meat intake (low vs. high) with CYP1A1 rs1048943 and CYP1B1 rs10175338 SNPs.

CONCLUSIONS

Phase I metabolizing enzyme gene SNPs may play a role in breast cancer development and may modify the grilled-smoked meat intake-breast cancer association.

Association between inflammatory potential of diet and risk of depression in middle-aged women: the Australian Longitudinal Study on Women's Health

Dietary factors and inflammation markers have been shown to play a role in the development of depression. However, there are very few studies that have explored the association between inflammatory potential of diet and risk of depression. In this study, we examined the association between the dietary inflammatory index (DII), which was developed specifically to measure the inflammatory potential of diet, and risk of depression in the middle-aged cohort of the Australian Longitudinal Study on Women's Health. A total of 6438 women with a mean age of 52·0 (sd 1·4) years at baseline were followed-up at five surveys over 12 years (2001-2013). Depression was defined as a score of ≥10 on the Center for Epidemiologic Studies Depression-10 scale. The DII score, a literature-derived, population-based dietary index that has been validated against several inflammatory markers, was computed on the basis of dietary intake assessed using a validated FFQ. Generalised estimating equations were used to estimate relative risk (RR) of depression according to DII score. Models were adjusted for energy intake, highest education completed, marital status, menopause status and symptoms, personal illness or injury, smoking status, physical activity, BMI and depression diagnosis or treatment. In total, 1156 women (18 %) had scores≥10 on the CESD scale over the course of 9 years. Women with the most anti-inflammatory diet had an approximately 20 % lower risk of developing depression compared with women with the most pro-inflammatory diet (RRDII quartile 1 v. 4: 0·81; 95 % CI 0·69, 0·96; P trend=0·03). These results suggest that an anti-inflammatory diet is associated with lower risk of depression in middle-aged Australian women.

Dietary Inflammatory Index and Risk of Multiple Sclerosis in a Case-Control Study from Iran

BACKGROUND

Diet and inflammation have been suggested to be important risk factors for multiple sclerosis (MS).

OBJECTIVES

In this study, we examined the ability of the dietary inflammatory index (DII) to predict MS in a case-control study conducted in Iran.

METHODS

This study included 68 MS cases and 140 controls hospitalized for acute non-neoplastic diseases. The DII was computed based on dietary intake assessed by a previously validated food frequency questionnaire. Logistic regression models were used to estimate ORs adjusted for age, energy, sex, body mass index, season of birth, rubella history, history of routine exercise before MS, smoking and history of consumption of cow's milk in the first 2 years of life.

RESULTS

Subjects with higher DII scores (i.e., with a more pro-inflammatory diet) had a higher risk of MS, with the DII being used both as a continuous variable (ORcontinuous 1.66; 95% CI 1.19-2.31; 1 unit increase corresponding to ≈15% of its range in the current study) and a categorical variable (ORDII (>1.43 vs.≤1.43) 2.68; 95% CI 1.15-6.26).

CONCLUSIONS

These results indicate that a pro-inflammatory diet is associated with increased risk of MS.

Inflammatory Potential of Diet and Risk of Ulcerative Colitis in a Case-Control Study from Iran

Diet and inflammation have been suggested to be important risk factors for ulcerative colitis (UC). In this case-control study conducted in Iran, we examined the ability of the dietary inflammatory index (DII) to predict UC. This study included 62 UC cases and 124 controls hospitalized for acute non-neoplastic diseases. The DII was computed based on dietary intake assessed by a previously validated food frequency questionnaire. Multivariable logistic regression models were used to estimate odds ratios (ORs) and the DII was analyzed as both continuous and as tertiles. Energy was adjusted using the residual method. Subjects with higher DII scores (i.e., with a more pro-inflammatory diet) had a higher risk of UC, with the DII being used as both a continuous variable (OR(continuous) 1.55, 95% confidence interval (CI) 1.04-2.32; one unit increase corresponding to ≈8% of its range in the current study) and as tertiles (OR(tertile3vstertile1) 2.58, 95% CI 1.03-6.48, P(trend)| = |0.04). These results indicate that a pro-inflammatory diet is associated with increased risk of UC.

Inflammatory potential of diet and all-cause, cardiovascular, and cancer mortality in National Health and Nutrition Examination Survey III Study

BACKGROUND

Various dietary components have been studied in relation to overall mortality; however, little is known about the relationship between the inflammatory potential of overall diet and mortality.

MATERIALS AND METHODS

We examined the association between the dietary inflammatory index (DII) and mortality in the National Health and Nutrition Examination Survey III follow-up study. The DII was computed from baseline dietary intake assessed using 24-h dietary recalls (1988-1994). Mortality was determined from the National Death Index records through 2006. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95 % confidence interval (95 % CI). During the follow-up, 2795 deaths were identified, including 1233 due to cardiovascular disease (CVD), and 615 due to cancer, 158 of which were due to digestive-tract cancers.

RESULTS

Multivariate Cox proportional hazards regression analyses, adjusting for age, race, diabetes status, hypertension, physical activity, body mass index, poverty index, and smoking, revealed positive associations between higher DII scores and mortality. Comparing subjects in DII tertile 3 versus tertile 1, significant associations were noted for all-cause mortality (HR_Tertile3vs1 1.34; 95 % CI 1.19-1.51, P _trend < 0.0001), CVD mortality (HR_Tertile3vs1 1.46; 95 % CI 1.18-1.81, P _trend = 0.0006), cancer mortality (HR_Tertile3vs1 1.46; 95 % CI 1.10-1.96, P _trend = 0.01), and digestive-tract cancer mortality (HR_Tertile3vs1 2.10; 95 % CI 1.15-3.84, P _trend = 0.03).

CONCLUSION

These results indicate that a pro-inflammatory diet, as indicated by higher DII scores, was associated with higher risk of all-cause, CVD, and cancer mortality.

Association between inflammatory potential of diet and mortality among women in the Swedish Mammography Cohort

PURPOSE

Diet and dietary components have been studied previously in relation to mortality; however, little is known about the relationship between the inflammatory potential of overall diet and mortality.

MATERIALS AND METHODS

We examined the association between the Dietary Inflammatory Index (DII) and mortality among 33,747 participants in the population-based Swedish Mammography Cohort. The DII score was calculated based on dietary information obtained from a self-administered food frequency questionnaire. Mortality was determined through linkage to the Swedish Cause of Death Registry through 2013. Cox proportional hazard regression was used to estimate hazard ratios (HR). During 15 years of follow-up, 7095 deaths were identified, including 1996 due to cancer, 602 of which were due to digestive-tract cancer, and 2399 due to cardiovascular disease.

RESULTS

After adjusting for age, energy intake, education, alcohol intake, physical activity, BMI, and smoking status, analyses revealed a positive association between higher DII score and all-cause mortality. When used as a continuous variable (range -4.19 to 5.10), DII score was associated with all-cause mortality (HRContinuous = 1.05; 95 % CI 1.01-1.09) and digestive-tract cancer mortality (HRContinuous = 1.15; 95 % CI 1.02-1.29). Comparing subjects in the highest quintile of DII (≥1.91) versus the lowest quintile (DII ≤ -0.67), a significant association was observed for all-cause mortality (HR = 1.25; 95 % CI 1.07-1.47, P trend = 0.003).

CONCLUSION

These results indicate that a pro-inflammatory diet, as indicated by higher DII score, was associated with all-cause and digestive-tract cancer mortality.

Association between inflammatory potential of diet and mortality in the Iowa Women's Health study

PURPOSE

Chronic diseases such as cancer and cardiovascular disease (CVD) are well-established causes of disability and premature deaths. Dietary components that are known to affect chronic inflammation have been implicated in the etiology and prognosis of these chronic diseases. We examined the ability of the dietary inflammatory index (DII) to predict overall, cancer and CVD mortality in the Iowa Women's Health study.

METHODS

The DII was computed from baseline dietary intake assessed in this cohort of 37,525 women, who were aged 55-69 years when enrolled starting in 1986. During the follow-up period, through December 31, 2010, in a total of 17,793 deaths, 5044 cancer- and 6528 CVD-related deaths were identified through mortality record linkage. Cox proportional hazards regression was used to estimate hazard ratios (HR) with DII expressed both as a continuous variable and as quartiles.

RESULTS

Comparing subjects in DII Quartile 4 versus Quartile 1, modest positive associations were noted for all-cause mortality (HRQ4vsQ1 1.07; 95 % CI 1.01-1.13; p-trend = 0.006), digestive cancer mortality (HRQ4vsQ1 1.19; 95 % CI 1.00-1.43; p-trend = 0.05), CVD mortality (HRQ4vsQ1 1.09; 95 % CI 1.01-1.18; p-trend = 0.08), non-cancer/non-CVD/non-acute mortality (HRQ4vsQ1 1.09; 95 % CI 1.00-1.19; p-trend = 0.19), coronary heart disease (CHD) mortality (HRQ4vsQ1 1.17; 95 % CI 1.05-1.30; p-trend = 0.001) and chronic obstructive pulmonary disease (COPD) mortality (HRQ4vsQ1 1.43; 95 % CI 1.18-1.75; p-trend = 0.0006). No substantial associations were observed for mortality from stroke, Alzheimer's disease or unspecified dementia.

CONCLUSION

These results indicate that a pro-inflammatory diet, as evidenced by higher DII scores, may be associated with total mortality as well as mortality from digestive cancer, CVD, CHD and COPD.

Short- and long-term reliability of adult recall of vegetarian dietary patterns in the Adventist Health Study-2 (AHS-2)

Past dietary patterns may be more important than recent dietary patterns in the aetiology of chronic diseases because of the long latency in their development. We developed an instrument to recall vegetarian dietary patterns during the lifetime and examined its reliability of recall over 5·3 and 32·6 years on average. The short-term/5-year recall ability study (5-RAS) was done using 24 690 participants from the cohort of the Adventist Health Study-2 (mean age 62·2 years). The long-term/33-year recall ability study (33-RAS) included an overlap population of 1721 individuals who joined the Adventist Health Study-1 and Adventist Health Study-2 (mean age 72·5 years). Spearman correlation coefficients for recall of vegetarian status were 0·78 and 0·72 for the 5-RAS and 33-RAS, respectively, when compared with 'reference' data. For both time periods sensitivity and positive predictive values were highest for the lacto-ovo-vegetarian and non-vegetarian patterns (vegans, lacto-ovo-vegetarians, pesco-vegetarians, semi-vegetarians and non-vegetarians). In the 5-RAS analyses, male, non-black, younger, and more educated participants, lifetime Adventists, and those with more stability of consumption of animal products generally showed higher recall ability. Somewhat similar tendencies were shown for the 33-RAS analyses. Our findings show that the instrument has higher reliability for recalled lacto-ovo-vegetarian and non-vegetarian than for vegan, semi- and pesco-vegetarian dietary patterns in both short- and long-term recalls. This is in part because these last dietary patterns were greatly contaminated by recalls that correctly would have belonged in the adjoining category that consumed more animal products.

Reliability of meat, fish, dairy, and egg intake over a 33-year interval in Adventist Health Study 2

We studied Adventist Health Study 2 (AHS-2) cohort members to determine the reliability of long-term recall of adult dietary intake that occurred 33 years ago. Establishing the reliability of these measures supports studies of how dietary exposure across the life course affects risk of cancer and other noncommunicable disease outcomes. Among 1816 AHS-2 cohort members, we conducted a statistical comparison of long-term recall of meat, fish, dairy, and eggs at AHS-2 baseline with their report of current diet 33 years before AHS-2 baseline at an age of 30-60 years. Major findings are as follows: 1) a high correlation for frequency of red meat (R = 0.71), poultry (R = 0.67), and fish (R = 0.60); lower correlations for dairy (R = 0.19) and eggs (R = 0.28); 2) good concordance for dichotomous measures of red meat [sensitivity: 0.70; specificity: 0.92; positive predictive value (PPV): 0.91], poultry (sensitivity: 0.76; specificity: 0.87; PPV: 0.83), fish (sensitivity: 0.61; specificity: 0.93; PPV: 0.89), dairy (sensitivity: 0.95; specificity: 0.57; PPV: 0.99), and eggs (sensitivity: 0.95; specificity: 0.41; PPV: 0.96); negative predictive value for dairy and eggs was poor. Among older AHS-2 cohort members, we found good reliability of recall of red meat, poultry, and fish intake that occurred 33 years earlier.

Searching for a link between the L-BMAA neurotoxin and amyotrophic lateral sclerosis: a study protocol of the French BMAALS programme

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is the most common motor neurone disease. It occurs in two forms: (1) familial cases, for which several genes have been identified and (2) sporadic cases, for which various hypotheses have been formulated. Notably, the β-N-methylamino-L-alanine (L-BMAA) toxin has been postulated to be involved in the occurrence of sporadic ALS. The objective of the French BMAALS programme is to study the putative link between L-BMAA and ALS.

METHODS AND ANALYSIS

The programme covers the period from 1 January 2003 to 31 December 2011. Using multiple sources of ascertainment, all the incident ALS cases diagnosed during this period in the area under study (10 counties spread over three French regions) were collected. First, the standardised incidence ratio will be calculated for each municipality under concern. Then, by applying spatial clustering techniques, overincidence and underincidence zones of ALS will be sought. A case-control study, in the subpopulation living in the identified areas, will gather information about patients' occupations, leisure activities and lifestyle habits in order to assess potential risk factors to which they are or have been exposed. Specimens of drinking water, food and biological material (brain tissue) will be examined to assess the presence of L-BMAA in the environment and tissues of ALS cases and controls.

ETHICS AND DISSEMINATION

The study has been reviewed and approved by the French ethical committee of the CPP SOOM IV (Comité de Protection des Personnes Sud-Ouest & Outre-Mer IV). The results will be published in peer-reviewed journals and presented at national and international conferences.

Dietary inflammatory index and risk of colorectal cancer in the Iowa Women's Health Study

BACKGROUND

Colorectal cancer, the third most common cancer in the United States, has a natural history that usually encompasses several decades. Dietary components have been implicated in the etiology of colorectal cancer, perhaps through their effect on inflammation.

METHODS

We examined the ability of the dietary inflammatory index (DII) to predict colorectal cancer in the Iowa Women's Health Study. The DII was computed based on dietary intake assessed by a 121-item food frequency questionnaire in this cohort of 34,703 women, ages 55 to 69 years, free of any self-reported prior malignancy at enrollment in 1986. Incident colorectal cancer cases were identified through linkage with the State Health Registry of Iowa (a Surveillance, Epidemiology, and End Results program member). Cox proportional hazards regression was used to estimate HRs. Through the end of 2010, 1,636 incident colorectal cancers were identified, including 1,329 colon and 325 rectal cancers.

RESULTS

Multivariable analysis, adjusting for body mass index, smoking status, pack-years of smoking, hormone replacement therapy, education, diabetes, and total energy intake, revealed positive associations between higher DII and colorectal cancer risk [HR for DIIcontinuous: 1.07 per unit increase in DII (corresponding to 0.5 SD unit increase); 95% confidence interval (CI), 1.01-1.13; HR for DIIquintiles: Q5 vs. Q1 = 1.20; 95% CI, 1.01-1.43]. HRs for DII were similar for colon cancer and rectal cancer, though not statistically significant for rectal cancer.

CONCLUSIONS

These results indicate that a proinflammatory diet, as indicated by higher DII scores, was associated with higher risk of developing colorectal cancer.

IMPACT

Proinflammatory diets are associated with increased risk of colorectal cancer.

Is soy intake related to age at onset of menarche? A cross-sectional study among adolescents with a wide range of soy food consumption

Background

Early onset of menarche may negatively influence the future health of adolescent girls. Several factors affect the timing of menarche but it is not clear if soy foods consumption around pubertal years plays a role; thus, we examined its relation to age at onset of menarche (AOM) in a high soy-consuming population.

Methods

We conducted a cross-sectional study on 339 girls ages 12–18 years attending middle and high schools near two Seventh-day Adventist universities in California and Michigan using a web-based dietary questionnaire and physical development tool. Soy consumption (categorized as total soy, meat alternatives, tofu/traditional soy, and soy beverages) was estimated from the questionnaire, while AOM was self-reported. Data analyses included descriptive statistics, Cox proportional hazards ratios, Kaplan-Meier curves and Poisson regression with adjustment for relevant confounders.

Results

Mean (SD) intakes were: total soy,12.9 (14.4) servings/week; meat alternatives, 7.0 (8.9) servings/week; tofu/traditional soy foods, 2.1 (3.8) servings/week; soy beverages, 3.8 (6.3) servings/week. Mean AOM was 12.5 (1.4) y for those who reached menarche. Consumption of total soy and the 3 types of soy foods was not significantly associated with AOM and with the odds for early- or late-AOM. Adjustment for demographic and dietary factors did not change the results.

Conclusion

Soy intake is not associated with AOM in a population of adolescent girls who have a wide range of, and relatively higher, soy intake than the general US population. Our finding suggests that the increasing popularity of soy in the US may not be associated with AOM.

Fiber intake and risk of nasopharyngeal carcinoma: a case-control study

Some studies examined the inverse relation between nasopharyngeal carcinoma (NPC) risk and dietary fibers in endemic populations. By means of a hospital-based case-control study, we verified whether this association was also present in Italy in connection with various types of dietary fibers. Cases were 198 patients with incident, histologically confirmed, NPC admitted to major teaching and general hospitals during 1992-2008. Controls were 594 patients admitted for acute, nonneoplastic conditions to the same hospital network of cases. Information was elicited using a validated food frequency questionnaire including 78 foods, food groups, or dishes. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated for quartiles of intake of different types of fiber after allowance for energy intake and other potential confounding factors. Total fiber intake was inversely related to risk of NPC (OR = 0.58 for the highest vs. the lowest quartile of intake; 95% CI: 0.34-0.96). We found an inverse association for total soluble (OR = 0.58; 95% CI: 0.35-0.96) and total insoluble fiber (OR = 0.56; 95% CI: 0.33-0.95), in particular cellulose (OR = 0.57; 95% CI: 0.33-0.96), and lignin (OR = 0.51; 95% CI: 0.31-0.85). In conclusion, this study suggests that dietary intake of soluble and insoluble fibers is inversely related to NPC risk in a nonendemic southern population.

Gestational vitamin D and the risk of multiple sclerosis in offspring

OBJECTIVE

Vitamin D may have a protective role in the etiology of multiple sclerosis (MS), but the effect of gestational vitamin D on adult onset MS has not been studied.

METHODS

In 2001, 35,794 mothers of participants of the Nurses' Health Study II completed a questionnaire inquiring about their experiences and diet during pregnancy with their nurse daughters. We studied the association of maternal milk intake, maternal dietary vitamin D intake, and predicted maternal serum 25-hydroxyvitamin D (25(OH)D) during pregnancy and their daughters' risk of developing MS.

RESULTS

MS was diagnosed in 199 women. The relative risk of MS was lower among women born to mothers with high milk or vitamin D intake during pregnancy. The multivariate adjusted rate ratio (RR) of MS was 0.62 (95% confidence interval [CI], 0.40-0.95; p trend = 0.001) for nurses whose mothers consumed 2 to 3 glasses of milk per day compared with those whose mothers consumed <3 glasses per month, and 0.57 (95% CI, 0.35-0.91; p trend = 0.002) for nurses with mothers in the highest quintile of dietary vitamin D intake compared with those in the lowest. The predicted 25(OH)D level in the pregnant mothers was also inversely associated with the risk of MS in their daughters. Comparing extreme quintiles, the adjusted RR was 0.59; (95% CI, 0.37-0.92; p trend = 0.002).

INTERPRETATION

Higher maternal milk and vitamin D intake during pregnancy may be associated with a lower risk of developing MS in offspring.

Validity of adolescent diet recall 48 years later

Few studies have evaluated the validity of adolescent diet recall after many decades. Between 1943 and 1970, yearly diet records were completed by parents of adolescents participating in an ongoing US study. In 2005-2006, study participants who had been 13-18 years of age when the diet records were collected were asked to complete a food frequency questionnaire regarding their adolescent diet. Food frequency questionnaires and diet records were available for 72 participants. The authors calculated Spearman correlation coefficients between food, food group, and nutrient intakes from the diet records and food frequency questionnaire and deattenuated them to account for the effects of within-person variation measured in the diet records on the association. The median deattenuated correlation for foods was 0.30, ranging from -0.53 for a beef, pork, or lamb sandwich to 0.99 for diet soda. The median deattenuated correlation for food groups was 0.31 (range: -0.48 for breads to 0.70 for hot beverages); for nutrient intakes, it was 0.25 (range: -0.08 for iron to 0.82 for vitamin B(12)). Some dietary factors were reasonably recalled 3-6 decades later. However, this food frequency questionnaire did not validly measure overall adolescent diet when completed by middle-aged and older adults on average 48 years after adolescence.

Food-frequency questionnaires: a review of their design, validation and utilisation

A review of the literature concerning the design, utilisation and validation of food-frequency questionnaires (FFQ) has been carried out using a semi-systematic approach to obtaining, reviewing and extracting data from articles. Databases were searched from 1980 to 1999. The present review identified 227 validation (from 1980 to September 1999) and 164 utilisation (for 1998 only) studies. A number of design issues have been evaluated through the present review. These include: the need to consider how portion sizes have been described, self-defined giving higher mean correlations; how an FFQ was administered, interviewer-administered giving higher mean correlations for some nutrients; how many items to include on an FFQ, those with the largest number of items having higher correlations. Validation techniques were described. Most validation studies involved comparing an FFQ against another dietary assessment method; only 19 % compared an FFQ to a biomarker. Measurement differences were most commonly assessed by correlation coefficients as opposed to other more appropriate methods. Mean correlation coefficients were highest for Ca and fat, and lowest for vitamin A and vegetables. The utilisation studies showed that FFQ were most commonly used in cross-sectional surveys, with ninety-three of the FFQ being designed to be disease-specific. The present review results were presented to a group of experts and a consensus arrived at concerning the development, validation and use of FFQ. Recommendations derived from the consensus arising from the literature review are presented as an appendix to the present paper.

Validity of maternal recall of preschool diet after 43 years

Validation of early childhood diet recalls by surrogate responders decades later has not been possible because of a lack of diet records from the distant past. Between 1948 and 1970, parents of children participating in the Fels Longitudinal Study (Kettering, Ohio) completed a 7-day diet record for their children every year from birth to age 18 years. In 2005-2006, all surviving women (n = 59) with a child aged 3-5 years when diet records had been collected were asked to complete a 42-item food frequency questionnaire (FFQ) pertaining to 1 of their children's diets at age 3-5 years. One or more diet records were available for 48 children. The authors calculated Spearman correlation coefficients for correlations between food, food-group, and nutrient intakes from the diet records and the FFQ and deattenuated them to account for the effects of within-person variation in the diet records on the association. For foods, the median deattenuated correlation coefficient was 0.19 (range, -0.31 to 0.85); moderate-to-high correlations were found for some specific foods. Correlations for food groups were slightly higher (median, 0.27; range, -0.14 to 0.85). Correlations for nutrient intakes were consistently low (median, 0.06; range, -0.35 to 0.27). Overall, the FFQ did not validly reflect overall preschool diet when completed by mothers 4 decades later.

Cooked meat and risk of breast cancer--lifetime versus recent dietary intake

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs) are carcinogens formed in or on the surface of well-done meat, cooked at high temperature.

METHODS

We estimated breast cancer risk in relation to intake of cooked meat in a population-based, case-control study (1508 cases and 1556 controls) conducted in Long Island, NY from 1996 to 1997. Lifetime intakes of grilled or barbecued and smoked meats were derived from the interviewer-administered questionnaire data. Dietary intakes of PAH and HCA were derived from the self-administered modified Block food frequency questionnaire of intake 1 year before reference date. Unconditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Modest increased risk was observed among postmenopausal, but not premenopausal, women consuming the most grilled or barbecued and smoked meats over the life course (OR = 1.47; CI = 1.12-1.92 for highest vs. lowest tertile of intake). Postmenopausal women with low fruit and vegetable intake, but high lifetime intake of grilled or barbecued and smoked meats, had a higher OR of 1.74 (CI = 1.20-2.50). No associations were observed with the food frequency questionnaire-derived intake measures of PAHs and HCAs, with the possible exception of benzo(alpha)pyrene from meat among postmenopausal women whose tumors were positive for both estrogen receptors and progesterone receptors (OR = 1.47; CI = 0.99-2.19).

CONCLUSIONS

These results support the accumulating evidence that consumption of meats cooked by methods that promote carcinogen formation may increase risk of postmenopausal breast cancer.

Adult recall of adolescent diet: reproducibility and comparison with maternal reporting

Many cancers have long latency periods, and dietary factors in adolescence may plausibly affect cancer occurrence in adulthood. Because of a lack of prospective data, retrospective collection of data on adolescent diet is essential. The authors evaluated a 124-item high school food frequency questionnaire (HS-FFQ) assessing diet during high school (15-35 years in the past) that was completed in 1998 by 45,947 US women in the Nurses' Health Study II (NHSII) cohort. To assess reproducibility, the authors readministered the HS-FFQ approximately 4 years later to 333 of these women. The mean Pearson correlation for 38 nutrient intakes was 0.65 (range, 0.50-0.77), and the mean Spearman rank correlation for food intakes was 0.60 (range, 0.37-0.77). Current adult diet was only weakly correlated with recalled adolescent diet (for nutrient intakes, mean r = 0.20). For assessment of validity, 272 mothers of the NHSII participants were asked to report information on their daughters' adolescent diets using the HS-FFQ. In this comparison, the mean Pearson correlation was 0.40 (range, 0.13-0.59) for nutrients, and the mean Spearman rank correlation for foods was 0.30 (range, 0.10-0.61). While further studies are warranted, these findings imply that this food frequency questionnaire provides a reasonable record of adolescent diet.

An approach for evaluating lifelong intakes of functional foods in elderly people

Many "functional foods" (FF), common foods with health benefits beyond their nutritive value, have antioxidant properties with the potential to mediate the degenerative changes of aging. A pilot study was conducted among 51 healthy, home-dwelling elderly people aged 70-86 y (51% male) to develop a method for evaluating relationships between lifelong diet and health. A population-based semiquantitative food frequency questionnaire (FFQ) was used to assess the usual diet. A nonquantitative questionnaire (FF-FFQ) was developed to examine current intake patterns of 33 FF, and at ages 65, 45, 25 and 10 y. Visual and memory cues were employed to help respondents remember past intakes, and their reporting confidence was queried. The instrument was self-administered (among 35%), or administered by a dietitian-interviewer in face-to-face (39%) or telephone (25%) interviews. The FFQ was validated by four dietary recalls statistically adjusted for intraindividual and seasonal variability. The FF-FFQ reliability was assessed in a subsample (n = 20). Mean usual FFQ-derived energy intakes were 7941 +/- 2071 kJ (men) and 7033 +/- 1916 kJ (women). Reported current, regular (several times/mo) FF numbered 18 +/- 4 (men) and 20 +/- 4 (women). These means decreased almost linearly with time; at age 10 y, FF reported were 12 +/- 7 (men) and 15 +/- 4 (women). Men differed from women in their memory of food consumption, food choices and FF intakes. Instrument reliability was good, with 73% identical responses. Food-related memory appears to be linked to dietary knowledge, food preparation experience and availability of foods in the past. The FF-FFQ provides novel data on lifetime FF consumption that may help clarify relationships between diet and health, and the role of diet in aging.

Development, validation and utilisation of food-frequency questionnaires - a review

OBJECTIVE

The purpose of this review is to provide guidance on the development, validation and use of food-frequency questionnaires (FFQs) for different study designs. It does not include any recommendations about the most appropriate method for dietary assessment (e.g. food-frequency questionnaire versus weighed record).

METHODS

A comprehensive search of electronic databases was carried out for publications from 1980 to 1999. Findings from the review were then commented upon and added to by a group of international experts.

RESULTS

Recommendations have been developed to aid in the design, validation and use of FFQs. Specific details of each of these areas are discussed in the text.

CONCLUSIONS

FFQs are being used in a variety of ways and different study designs. There is no gold standard for directly assessing the validity of FFQs. Nevertheless, the outcome of this review should help those wishing to develop or adapt an FFQ to validate it for its intended use.

Recall of diet during a past pregnancy

The authors conducted a study of women's ability to recall diet during a past pregnancy. For a prospective study, women completed self-administered food frequency questionnaires (FFQs) before and during pregnancy (1989-1992). These women, mostly White and well-educated, were contacted 3-7 years later (1996-1997) for a retrospective dietary assessment performed by either telephone interview (n = 154) or self-administered FFQ (n = 115). Energy-adjusted Pearson correlations ranged from 0.10 to 0.49 for the telephone interview group and from 0.02 to 0.67 for the self-administered questionnaire group. When participants' intakes were ranked, quintile agreement (within one quintile) between original diet and recalled diet ranged from 60% to 69% in the telephone interview group and from 69% to 79% in the self-administered questionnaire group. Correlations and percentages of agreement were higher among women who used the same questionnaire for both dietary assessments than among those who used different questionnaires. These results suggest that diet during pregnancy is recalled with similar accuracy as or perhaps slightly lower accuracy than adult diet generally. This may reflect, in part, the influence of current (nonpregnancy) diet on recall of past (pregnancy) diet. While the results of this study may not be generalizable to those obtained from other populations, to the authors' knowledge it is the first study of recall of diet during pregnancy.

[Using food frequency questionnaire in past dietary intake assessment]

This paper aims to discuss which one is the best estimator of past diet: a retrospective report or a recent diet recall. The analysis included 13 articles published between 1984-1997 and selected from a MEDLINE search and from other reviews on this subject. The selection criterion was the use of a food frequency questionnaire (FFQ) in a validation study of retrospective report of dietary intake in remote past. Literature review shows that even taking into account misclassification, retrospective report of diet usually yields to a more reliable estimate of past diet pattern than current report. Past diet recall was strongly influenced by current intake and by diet patterns change. Analyzed investigations indicate that agreement between original and retrospective report was higher either for foods eaten rarely or frequently and lower for foods moderately consumed. This review allows considering the FFQ as a valuable instrument when studying the role of diet on the etiology of chronic diseases.

Diet and the risk of breast cancer in a case-control study: does the threat of disease have an influence on recall bias?

It has been suggested that recall bias may explain the discrepant results between case-control and cohort studies on diet and the risk of breast cancer. Two control groups were used for this case-control study of 25 to 75-year-old breast cancer cases (n = 310). The first group consisted of population controls drawn from the Finnish National Population Register (n = 454). The second group consisted of women who were referred to the same examinations as were the cases because of clinical suspicion of breast disease but who were later diagnosed as healthy (referral controls; n = 506). Because the diagnosis was unknown at the time of interview, it was possible to assess by comparing the two control groups whether the self-reporting of diet changed under the threat of disease. Dietary habits were examined using a validated, self-administered food-frequency questionnaire. Premenopausal women misreported their consumption of liquid milk products, tea, and sugar. Reporting bias was also associated with the intake of fat and vitamins. Postmenopausal women misreported consumption of milk products. When recall bias was taken into consideration, milk was associated with increased risk of premenopausal breast cancer, whereas high consumption of poultry or high intake of monounsaturated fatty acids, n-3 fatty acids, n-6 fatty acids, and vitamin E were related to lower risk. The study suggested that oil, milk, cheese, coffee and beta-carotene may act as protective factors in postmenopausal women, whereas butter and cream may be risk factors for breast cancer. In summary, it is possible that some food items may be overreported or underreported under the threat of disease in health-conscious population. However, most of the results in this study were not modified by recall bias.

Reliability of retrospective information on diet 20 years ago and consistency of independent measurements of remote adolescent diet

Although dietary exposures in the distant past are considered important in the etiology of several diseases, few studies have addressed methodological aspects of long-term (> or = 20 yrs) recall. We evaluated the reliability of retrospective self-reports about diet 20 years before the interview and consistency (between siblings) of self-reports about diet during adolescence in a population-based case-control study of stomach cancer in Sweden. Short-term reliability (a questionnaire self-administered 9-12 mos after the personal interview) of reports on diet 20 years ago by 374 control subjects showed mean correlation coefficients for 42 foods/beverages of 0.41 (Pearson) and 0.46 (Spearman) and a mean weighted kappa statistic of 0.42; for 15 nutrients/food constituents the corresponding mean values were 0.46, 0.47, and 0.42, respectively. Consistency of independent reports by siblings about their own diet during adolescence studied in 201 control-sibling pairs was modest. The mean Pearson correlation coefficient for 33 foods/beverages was 0.29, and the mean weighted kappa statistic was 0.30; at the nutrient level the means were 0.26 and 0.24, respectively. A comparison of intersibling differences between controls and stomach cancer cases revealed correlations of a similar magnitude (mean Pearson correlation for 33 foods = 0.29 for control-sibling and 0.27 for case-sibling pairs), thus contradicting differential recall. Our results imply that although reliability of self-reports about the diet in the distant past is generally lower than for the actual diet, we can use these measurements when remote time periods are of special interest in etiological epidemiologic studies.

Reproducibility of recall of adolescent diet: Nurses' Health Study (United States)

Although diet and alcohol consumption at a younger age have been hypothesized to play an etiologic role in adult malignancy, few studies have addressed these relations and few data exist on the ability to measure recalled diet during adolescence. We undertook a study to determine whether the recall of diet during high school 22 to 47 years later was reproducible within a prospective cohort of women. In 1986, participants in the Nurses' Health Study (United States), aged 40 to 65 years, reported their diet during high school using a 24-item food frequency questionnaire (FFQ). On the 1988 questionnaire, the participants recorded their alcohol consumption between the ages of 18 and 22. In 1994, a random sample of 275 women were asked to record again their high school diet and alcohol consumption. The average of Spearman correlations between the two recalls of high school diet was r = 0.57 (range = 0.38 to 0.74). For alcohol intake, the correlation for the time period queried was 0.66. The correlation between the two recalls of high school diet was higher than the correlation between the first recall and current diet in 1986 (average r = 0.25). There was no effect of age on reproducibility of recall. These data suggest that recall of diet from the very distant past, during a distinct time period such as high school, is reasonably reproducible. Although further studies of validity are needed, such information may be sufficiently precise to assess the influence of remote diet in epidemiologic studies.

Reproducibility of food intake in a food frequency questionnaire used in a general population

This study evaluates the reproducibility of food intake reports in a 45-item self-administered food frequency questionnaire (FFQ) used for a diet study in a large cohort in New York State. The first FFQ was mailed in 1980, and a followup version containing 75 food items was mailed in 1988 to the eligible original participants. Reproducibility was evaluated by comparing the subjects' 1988 responses with their original 1980 responses. Spearman's correlations ranged from 0.27 (nuts other than peanuts) to 0.56 (summer squash) in men and from 0.25 (tomatoes) to 0.51 (summer squash) in women. Analyses stratified by age, education, marital status, body mass index, cigarette smoking, alcohol drinking, and special diet revealed few substantial differences in correlations. The moderate reproducibility of foods in this questionnaire indicates that brief FFQs may be a useful tool to study food intake and chronic disease relationships in this population.

Recall bias in the association of micronutrient intake and breast cancer

A nested case-control study within the Canadian National Breast Screening Study was conducted to examine whether there was evidence for recall bias in the reporting of past micronutrient intake. Dietary data collected upon enrollment between 1982 and 1985 from 325 breast cancer cases and 628 matched controls were compared with data collected in 1988 after disease diagnosis. The retrospective estimates of mean micronutrient intakes from food sources were found to be very similar to the prospective estimates for cases and controls. Errors of omission and commission for the reporting of previous supplementary vitamin use were identical for both subject groups. The odds ratios estimated for the association of micronutrient intake and breast cancer for the prospective and retrospective data were similar in magnitude and the 95% confidence intervals overlapped considerably. There was no evidence for recall bias in the estimation of past micronutrient intake by breast cancer cases as compared to controls.

A case-control study of oral cancer in Beijing, People's Republic of China. Associations with nutrient intakes, foods and food groups

A case-control study of oral cancer was conducted in Beijing, People's Republic of China to examine the association between dietary nutrient intake and risk of oral cancer, both in terms of estimated intake of nutrients and micro-nutrients, and in terms of specific foods and food groups. The study was hospital-based and controls were hospital in-patients matched for age and sex with the cases. The response rate for cases and controls was 100% and 404 case/control pairs were interviewed. The results suggest that increased protein and fat intake are related to a decreased risk of oral cancer. Carbohydrate intake, however, showed a moderate increased risk for oral cancer. Total carotene intake and carotene intake from fruits and vegetables are inversely associated with risk of oral cancer. A similar pattern was observed for dietary vitamin C intake. Dietary fibre derived from fruits and vegetables showed a strong negative association with oral cancer risk, but fibre derived from other sources did not exhibit any protective effect. At the level of foods and food groups, increased consumption of fresh meat, chicken and liver was significantly associated with a reduction in oral cancer risk: the tests for trend were all statistically significant at the P < 0.01 level. Consumption of common carp, hairtail, shrimp and lobster were also associated with decreased risk. Risk was found to increase with increasing consumption of millet and corn bread (P < 0.01) but to decrease with increasing consumption of rice (P < 0.01). Increased consumption of grapes, bananas, oranges, tangerines, peaches and pears were associated with reduced risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Husband-wife diet concordance and changes in dietary practices by surviving spouses of cancer cases

Diet concordance and changes in dietary practices by surviving spouses of cancer cases were investigated by studying 69 husband-wife pairs during an eight-year period spanning the death from cancer of one spouse. The data base consisted of reports for each cancer case from the Adventist Health Study (AHS) where a surviving spouse was available. Two questions were addressed. 1. Do husbands and wives eat similar diets? 2. Did survivors change their diet practices during the eight-year period? Three sets of dietary data were compared with the AHS food frequency questionnaire: reports made in 1976 by cases; reports made in 1976 by their spouses (initial); and the spouses' reports in 1984 (current). Diet concordance and dietary changes for 35 key food groups were evaluated both for individual foods and across foods by computing recall scores. The results were analyzed with univariate and multivariate methods. Comparison of means and Spearman rank-order correlations revealed good initial concordance between the spouses, which was not significantly related to age, sex, or education. However, eight years later subsequent to the deaths of the cases, the agreement was poor because the surviving spouses had changed their diets. The changes in dietary practices were significantly related to education and body mass index in univariate analysis but not in analysis of covariance. These results indicate that retrospective recall by spouses for the cases rather than the spouses' own current reports should be used as an estimate for the deceased cases. Repeated recalls are necessary to increase reliability.

Chronic disease among Seventh-day Adventists, a low-risk group. Rationale, methodology, and description of the population

The Adventist Health Study is a prospective cohort study of 34,198 non-Hispanic white Seventh-day Adventists (13,857 men; 20,341 women, age 25-100 years) followed for 6 years (1977-1982). Within this population, 55.2% were lacto-ovovegetarian (consumed meat, poultry, or fish less than one time per week with no restrictions as to egg or dairy product consumption) in 1976 and most abstained from alcohol, tobacco, and pork products. Baseline data included demographic variables, information on current and past dietary habits, exercise patterns, use of prescription drugs, use of alcohol and tobacco, measures of religiosity, occupation and residential histories, anthropometric data, and menstrual and reproductive histories. Nonfatal case ascertainment was completed through review of self-reported hospitalizations obtained from annual self-administered mailed questionnaires and through computerized record linkage with two California population-based tumor registries. Fatal case ascertainment was completed via record linkage with computerized California state death certificate files, the National Death Index, and individual follow-up. During the 6 years of follow-up, 52.8% of the 34,198 study subjects reported at least one hospitalization. A total of 20,702 medical charts were reviewed for cancer and cardiovascular disease incidence and 1406 incident cancer cases and 2716 deaths from all causes were identified after baseline data collection.