Relative validity of a food frequency questionnaire used in the Inter99 study

Evaluation of Web-based Dietary Assessment Software for Children: comparing reported fruit, juice and vegetable intakes with plasma carotenoid concentration and school lunch observations

Web-based Dietary Assessment Software for Children (WebDASC) was developed to estimate dietary intake in a school meal intervention study among 8- to 11-year-old Danish children. The present study validates self-reported fruit, juice and vegetable (FJV) intakes in 8- to 11-year-old children by comparing intake with plasma carotenoid concentration, and by comparing the reported FJV intake to actually eaten FJV, as observed by a photographic method. A total of eighty-one children, assisted by parents, reported their diet for seven consecutive days. For the same five schooldays as they reported their diet, the children's school lunch was photographed and weighed before and after eating. In the week after the diet reporting, fasting blood samples were taken. Self-reported intake of FJV and estimated intake of carotenoids were compared with plasma carotenoid concentration. Accuracy of self-reported food and FJV consumption at school lunch was measured in terms of matches, intrusion, omission and faults, when compared with images and weights of lunch intake. Self-reported intake of FJV was significantly correlated with the total carotenoid concentration (0·58) (P< 0·01). Fruit and juice consumption showed higher correlations than vegetables with plasma carotenoid concentration (0·38 and 0·42 v. 0·33) (P< 0·01). A total of 82 % of the participants fell into the same or adjacent quartiles when cross-classified by FJV intake and carotenoids biomarkers. WebDASC attained 82 % reporting matches overall and a higher percentage match for reporting fruits compared with beverages. The present study indicated that WebDASC can be used to rank 8- to 11-year-old Danish children according to their intake of FJV overall and at school meals.

Validity and reliability of a dish-based, semi-quantitative food frequency questionnaire for Korean diet and cancer research

This study evaluated the validity and reliability of applying a newly developed dish-based, semi-quantitative food frequency questionnaire (FFQ) for Korean diet and cancer research. The subjects in the present study were 288 Korean adults over 30 years of age who had completed two FFQs and four 3-day diet records (DRs) from May 2008 to February 2009. Student's t-tests, Chi-square tests, and Spearman's rank correlation coefficients were used to estimate and compare intakes from different dietary assessment tools. Agreement in quintiles was calculated to validate agreement between the results of the second FFQ (FFQ-2) conducted in February 2009 and the DRs. Median Spearman's correlation coefficients between the intake of nutrients and foods assessed by the FFQ-1 and FFQ-2 were 0.59 and 0.57, respectively, and the coefficients between the intake of nutrients and foods assessed by the FFQ-2 and the DRs were 0.31 and 0.29, respectively. The quintile classifications of same or adjacent quintile for intake of nutrients and foods were 64% and 65%, respectively. Misclassification into opposite quintiles occurred in less than 5% for all dietary factors. Thus this newly-developed, Korean dish-based FFQ demonstrated moderate correspondence with the four 3-day DRs. Its reliability and validity are comparable to those reported in other studies.

Vitamin D status and changes in cardiovascular risk factors: a prospective study of a general population

OBJECTIVES

A low vitamin D level has been associated with increased cardiovascular disease risk but possible mechanisms remain unclear. We investigated the association between vitamin D levels and 5-year changes in blood pressure, lipid profile and incidence of the metabolic syndrome, hypertension and hypercholesterolemia.

METHODS

A random sample of 6,784 individuals aged 30-60 years from a general population was investigated in the Inter99 study in 1999-2001. Vitamin D (serum 25-hydroxyvitamin D) was measured at baseline by high-performance liquid chromatography, and 4,330 individuals participated at the 5-year follow-up and were included in the present study.

RESULTS

The median baseline vitamin D concentration was 48.0 nmol/l. In multivariable linear regression analyses, a 10 nmol/l higher baseline level of vitamin D was associated with a decrease in triglycerides and very low density lipoprotein cholesterol by 0.52 (p = 0.03) and 0.66% (p = 0.005), respectively. In multivariable logistic regression analyses, the odds ratios per 10 nmol/l higher baseline vitamin D level were 0.95 (p < 0.05) and 0.94 (p = 0.01) for the development of the metabolic syndrome and hypercholesterolemia, respectively. There was no association between vitamin D and blood pressure.

CONCLUSIONS

An optimal vitamin D status may influence cardiovascular health by changing the lipid profile in a favorable direction and decreasing the incidence of the metabolic syndrome.

The effects of high-load strength training with protein- or nonprotein-containing nutritional supplementation in patients undergoing dialysis

OBJECTIVE

The aim of this study was to investigate the effects of high-load strength training and protein intake in patients undergoing dialysis with a focus on muscle strength, physical performance, and muscle morphology.

DESIGN

This was a randomized controlled study conducted in three dialysis centers.

SUBJECTS

Subjects for the study included 29 patients undergoing dialysis.

INTERVENTION

The participants went through a control period of 16 weeks before completing 16 weeks of strength training. Before the training period, the participants were randomly assigned to receive a protein or a nonprotein drink after every training session.

MAIN OUTCOME MEASURE

Muscle strength and power were tested using the good strength equipment and the leg extensor power rig. Physical performance and function were assessed using a chair stand test and the Short Form 36 questionnaire. Muscle fiber type size and composition were analyzed in biopsies obtained from the m. vastus lateralis.

RESULTS

All variables remained unchanged during the control period. After training, muscle strength and power, physical performance, and physical function increased significantly. Muscle fiber composition was changed by a relative decrease in type 2x muscle fiber number whereas muscle size at the fiber level was unchanged. There were no effects of combining the training with protein intake.

CONCLUSIONS

High-load strength training is associated with improvements in muscle strength and power, physical performance, and quality of life. The effects were surprisingly not associated with muscle hypertrophy, and the results did not reveal any additional benefit of combining the training with protein intake. The positive results in muscle strength and physical performance have clinically relevant implications in the treatment of patients undergoing dialysis.

The relationship between changes in health behaviour and initiation of lipid-lowering and antihypertensive medications in individuals at high risk of ischaemic heart disease

BACKGROUND

It has been hypothesised that health conscious individuals tend to take better care of themselves by greater adherence to preventive medications. We examined, whether long-term changes in dietary habits and physical activity were associated with initiation of lipid-lowering and antihypertensive medications.

METHODS

The study population consisted of two subsamples from the population-based cohort Inter99 study (1999-2006) in Copenhagen, Denmark: one with systolic blood pressure > 140 mmHg (N = 557) and one with total cholesterol > 7 mmol/L (N = 314). At a health examination, individuals completed a questionnaire about health behaviour and had their blood pressure and cholesterol measured at baseline and after five years. Data on medications were obtained through linkage to the Registry of Medical Product Statistics.

RESULTS

Positive changes in physical activity (odds ratio =3.50; 95% CI 1.23-7.54) and in dietary habits (odds ratio = 2.08; 95% CI 1.03-4.21) were associated with an increased initiation of lipid-lowering medications. With respect to antihypertensives, no association was observed in terms of physical activity, but for diet, a positive trend in terms of initiation was observed among those with positive changes in dietary habits (odds ratio = 1.58; 95% CI 0.96-2.59).

CONCLUSION

Generally, we observed health conscious behaviour in terms of increased initiation of preventive medications among those who reported positive changes in health behaviour. This study therefore suggests that more attention should be given to identifying individuals and groups, who are less health conscious and thereby less likely to engage in either preventive medications or changes in health behaviours.

Evaluation of flavonoids and enterolactone in overnight urine as intake biomarkers of fruits, vegetables and beverages in the Inter99 cohort study using the method of triads

Since collection of 24 h urine samples is very time consuming and difficult to obtain, epidemiological studies typically only obtain spot urine samples. The aim of the present study was to evaluate whether flavonoids and enterolactone in overnight urine could substitute flavonoids and enterolactone in 24 h urine as an alternative and more feasible biomarker of fruit, vegetable and beverage intake. A total of 191 individuals in the Inter99 cohort in Denmark completed the validation study. Concentrations of nine urinary flavonoid aglycones (quercetin, isorhamnetin, tamarixetin, kaempferol, hesperetin, naringenin, eriodictyol, phloretin and apigenin) and enterolactone were determined in overnight and 24 h urine samples, and their validity as biomarkers of fruit, vegetable and beverage intake was evaluated in relation to two independent reference methods (Inter99 FFQ data and plasma carotenoids) by using the method of triads. The intakes of fruit, juice, vegetables and tea reported in the FFQ were reflected by the flavonoid biomarker both in overnight and 24 h urine samples. Validity coefficients for the flavonoid biomarker in overnight urine ranged from 0·39 to 0·49, while the corresponding validity coefficients for the biomarker in 24 h urine ranged from 0·43 to 0·66. Although the validity coefficients were lower for overnight urine than for the 24 h urine flavonoid biomarker, they were still of acceptable magnitude. In conclusion, the results indicate that flavonoids and enterolactone in overnight urine samples may be used as a more feasible biomarker than 24 h urine for the assessment and validation of fruit, juice, vegetable and tea intakes in epidemiological studies.

Determinants of vitamin D status in a general population of Danish adults

BACKGROUND AND AIMS

Danish legislation regarding food fortification has been very restrictive and vitamin D deficiency is thought to be common in Denmark due to inadequate dietary intakes and the fact that in Denmark (latitude 56°N) vitamin D is only synthesized in the skin after exposure to solar radiation during summertime (April-September). The purpose of this study was to evaluate the vitamin D status of a general adult population in Denmark and, in addition, associations between vitamin D status and distinct lifestyle factors were studied.

METHODS

A random sample of 6784 persons from a general population aged 30-60 years participated in a health examination in 1999-2001. Serum samples from all participants were stored and levels of 25-hydroxyvitamin D (25(OH)D) were measured by HPLC in 2009. The method was compared to another HPLC method. Information on dietary intake of vitamin D and other lifestyle factors were obtained by questionnaires. A total of 6146 persons defined as ethnic Danes and with successful measurements of 25(OH)D were included in the analyses.

RESULTS

The overall prevalence of vitamin D deficiency (25(OH)D<25 nmol/l) and insufficiency (25(OH)D<50 nmol/l) were 13.8% and 52.2%, respectively. A marked seasonal fluctuation was seen in serum levels of 25(OH)D - median values of 25(OH)D were lowest in February and highest in August. In multiple logistic regression models (n=5506), low vitamin D status was significantly associated with obesity (BMI≥30), daily smoking and a sedentary lifestyle. However, measurements of 25(OH)D were not associated with the estimated dietary intake of vitamin D. Comparison of two HPLC methods demonstrated considerable differences in accuracy.

DISCUSSION AND CONCLUSIONS

Our results suggest that poor vitamin D status is common among adults in a Northern European country without food fortification with vitamin D. Methodological issues are, however, of great importance when using cut-off values to define poor vitamin D status. In addition, we demonstrated that low serum levels of 25(OH)D were associated with several lifestyle factors.

Predicting urinary creatinine excretion and its usefulness to identify incomplete 24 h urine collections

Studies using 24 h urine collections need to incorporate ways to validate the completeness of the urine samples. Models to predict urinary creatinine excretion (UCE) have been developed for this purpose; however, information on their usefulness to identify incomplete urine collections is limited. We aimed to develop a model for predicting UCE and to assess the performance of a creatinine index usingpara-aminobenzoic acid (PABA) as a reference. Data were taken from the European Food Consumption Validation study comprising two non-consecutive 24 h urine collections from 600 subjects in five European countries. Data from one collection were used to build a multiple linear regression model to predict UCE, and data from the other collection were used for performance testing of a creatinine index-based strategy to identify incomplete collections. Multiple linear regression (n458) of UCE showed a significant positive association for body weight (β = 0·07), the interaction term sex × weight (β = 0·09, reference women) and protein intake (β = 0·02). A significant negative association was found for age (β = − 0·09) and sex (β = − 3·14, reference women). An index of observed-to-predicted creatinine resulted in a sensitivity to identify incomplete collections of 0·06 (95 % CI 0·01, 0·20) and 0·11 (95 % CI 0·03, 0·22) in men and women, respectively. Specificity was 0·97 (95 % CI 0·97, 0·98) in men and 0·98 (95 % CI 0·98, 0·99) in women. The present study shows that UCE can be predicted from weight, age and sex. However, the results revealed that a creatinine index based on these predictions is not sufficiently sensitive to exclude incomplete 24 h urine collections.

Race-specific validation of food intake obtained from a comprehensive FFQ: the Adventist Health Study-2

OBJECTIVE

To assess race-specific validity of food and food group intakes measured using an FFQ.

DESIGN

Calibration study participants were randomly selected from the Adventist Health Study-2 (AHS-2) cohort by church, and then by subject-within-church. Intakes of forty-seven foods and food groups were assessed using an FFQ and then compared with intake estimates measured using six 24 h dietary recalls (24HDR). We used two approaches to assess the validity of the questionnaire: (i) cross-classification by quartile and (ii) de-attenuated correlation coefficients.

SETTING

Seventh-day Adventist church members geographically spread throughout the USA and Canada.

SUBJECTS

Members of the AHS-2 calibration study (550 whites and 461 blacks).

RESULTS

The proportion of participants with exact quartile agreement in the FFQ and 24HDR averaged 46 % (range: 29-87 %) in whites and 44 % (range: 25-88 %) in blacks. The proportion of quartile gross misclassification ranged from 1 % to 11 % in whites and from 1 % to 15 % in blacks. De-attenuated validity correlations averaged 0·59 in whites and 0·48 in blacks. Of the forty-seven foods and food groups, forty-three in whites and thirty-three in blacks had validity correlations >0·4.

CONCLUSIONS

The AHS-2 questionnaire has good validity for most foods in both races; however, validity correlations tend to be higher in whites than in blacks.

Association of dietary sodium and potassium intakes with albuminuria in normal-weight, overweight, and obese participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study

BACKGROUND

Among obese adults, sodium intake has been associated with cardiovascular disease. Few data are available on sodium intake and albuminuria, a marker of kidney damage and risk factor for cardiovascular disease.

OBJECTIVE

We examined the relation between dietary sodium and potassium intakes and the ratio of sodium to potassium (Na/K) with albuminuria by BMI in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study (n = 30,239 adults aged ≥45 y).

DESIGN

A modified Block 98 food-frequency questionnaire was used for dietary assessment in 21,636 participants, and nutritional variables were categorized by sex-specific quintiles. Normal weight, overweight, and obese were defined as BMI (in kg/m(2)) categories of 18.5-24.9, 25-29.9, and ≥30, respectively. Albuminuria was defined as a ratio (mg/g) of urinary albumin to creatinine of ≥30.

RESULTS

The prevalences of albuminuria were 11.5%, 11.6%, and 16.0% in normal-weight, overweight, and obese participants, respectively. The multivariable-adjusted ORs for albuminuria in a comparison of the highest with the lowest quintile of Na/K intake (≥1.12 to <0.70 for men and ≥1.07 to <0.62 for women) were 0.89 (95% CI: 0.65, 1.22), 1.08 (95% CI: 0.85, 1.36), and 1.28 (95% CI: 1.02, 1.61) in normal-weight, overweight, and obese participants, respectively. The highest quintile of dietary sodium was associated with an increased OR for albuminuria in obese participants (OR: 1.44; 95% CI: 1.00, 2.07) but not in normal-weight or overweight participants. Dietary potassium was not associated with albuminuria.

CONCLUSION

In obese adults, higher dietary Na/K and sodium intakes were associated with albuminuria.

Validity and reproducibility of a web-based, self-administered food frequency questionnaire

BACKGROUND/OBJECTIVES

To assess the validity and the reproducibility of a newly developed web-based, self-administered food frequency questionnaire (web-FFQ).

SUBJECTS/METHODS

A total of 74 healthy subjects (34 men and 40 women) from the Québec City metropolitan area were asked to complete, in random order, the web-FFQ, a validated interviewer-administered FFQ (IA-FFQ) and a 3-day food record (3-day FR).

RESULTS

Mean intakes of 17/22 nutrients assessed between the web-FFQ and the 3-day FR were not significantly different (differences <10%, P≥0.11). Sex and energy-adjusted de-attenuated Pearson correlation coefficients for each nutrient varied from 0.12-0.98 (mean R=0.55, 95% confidence interval 0.46; 0.63) between the web-FFQ and the 3-day FR. All correlations were significant (P≤0.01) and above 0.34 (mean R=0.59, 95% confidence interval 0.54; 0.65) between the web-FFQ and the IA-FFQ, except for sodium (R=0.17, P=0.14). Cross-classification analysis revealed that on average, 77% of subjects were classified in the same or adjacent quartile of nutrient intake between the web-FFQ and the 3-day FR. Correlation coefficients for reproducibility of the web-FFQ tested 4-6 weeks apart in the same individuals were all equal or above 0.48 (P≤0.0001; mean R=0.72, 95% confidence interval 0.68; 0.76). More than 90% of the subjects were classified in the same or adjacent quartile between the two administrations of the web-FFQ, while only 0.8% was misclassified.

CONCLUSIONS

These data demonstrate that the newly developed web-based FFQ appears to have reasonable validity and good reproducibility for assessing nutrient intakes at the group and individual levels in a population of healthy adults.

The effects of adding group-based lifestyle counselling to individual counselling on changes in plasma glucose levels in a randomized controlled trial: the Inter99 study

AIM

This study aimed to assess whether group-based lifestyle counselling offered to a high-risk population subgroup had any effect beyond individual multifactorial interventions on fasting plasma glucose (FPG) and 2-h plasma glucose (2hPG) changes.

METHODS

In a population-based study of 6784 participants, 4053 were determined to be at high risk based on a risk estimate of ischaemic heart disease or the presence of risk factors (smoking, hypertension, hypercholesterolaemia, obesity, impaired glucose tolerance). Of these subjects, 90% were randomized to high-intensity intervention (group A) and 10% to low-intensity intervention (group B). All participants went through health examinations, risk assessments and individual lifestyle counselling. Participants in group A were further offered group-based lifestyle counselling. The intervention was repeated after 1 and 3 years. A total of 2738 participants free of diabetes at baseline (1999-2001) and with at least one FPG and/or 2hPG measurement during 5 years of follow-up were included in the analyses. Differences in changes of plasma glucose between groups A and B were analyzed using multilevel linear regression.

RESULTS

For FPG, crude 5-year changes were significantly different between the two groups (group A: -0.003 mmol/L vs group B: -0.079 mmol/L; P=0.0427). After adjusting for relevant confounders, no differences in FPG changes were observed (P=0.116). Also, no significant differences in the 5-year changes in 2hPG between the two groups were observed (group A: - 0.127 mmol/L vs group B: -0.201 mmol/L; P=0.546).

CONCLUSION

Offering additional group-based intervention to a high-risk population subgroup had no clinical effects on changes in plasma glucose beyond those of individualized multifactorial interventions.

Effects of organic and conventional growth systems on the content of carotenoids in carrot roots, and on intake and plasma status of carotenoids in humans

BACKGROUND

The demand for organic food products has increased during the last decades due to their probable health effects, among others. A higher content of secondary metabolites such as carotenoids in organic food products has been claimed, though not documented, to contribute to increased health effects of organic foods. The aim was to study the impact of organic and conventional agricultural systems on the content of carotenoids in carrots and human diets. In addition, a human cross-over study was performed, measuring the plasma status of carotenoids in humans consuming diets made from crops from these agricultural systems.

RESULTS

The content of carotenoids in carrot roots and human diets was not significantly affected by the agricultural production system or year, despite differences in fertilisation strategy and levels. The plasma status of carotenoids increased significantly after consumption of the organic and conventional diets, but no systematic differences between the agricultural production systems were observed.

CONCLUSION

The expected higher content of presumed health-promoting carotenoids in organic food products was not documented in this study.

Atopy, asthma, and lung function in relation to folate and vitamin B(12) in adults

BACKGROUND

Recent studies suggested low serum folate and impaired folate metabolism as potential risk factors for development of asthma and atopic disease, but the results are inconsistent. The aim of this study was to investigate the relations of markers of folate and vitamin B₁₂ (B₁₂) deficiency with different phenotypes of asthma and atopy.

METHODS

A random sample of 6784 persons from a general population aged 30-60 years participated in a health examination in 1999-2001, and 4516 (66.6%) of those also participated in a follow-up examination 5 years later. The examinations included spirometry, measurements of serum folate and B₁₂, specific IgE to inhalant allergens, total IgE, and genotyping of the MTHFR-C677T polymorphism - a genetic marker of impaired folate metabolism. Information about dietary intake of folate and B₁₂, asthma diagnosis, and airway symptoms was obtained by questionnaires.

RESULTS

Low serum folate levels and the TT genotype of the MTHFR-C677T polymorphism were associated with increased prevalence of self-reported doctor-diagnosed asthma [odds ratio (OR) 1.37, 95% confidence interval (CI) 1.05-1.79 and OR 1.52; 95% CI 1.12-2.06, respectively] and attacks of shortness of breath (OR 1.43, 95% CI 1.14-1.79 and OR 1.47; 95% CI: 1.14-1.91, respectively). We found no significant associations with lung function or atopic outcomes. Serum levels of B₁₂ and dietary intake of folate and B₁₂ were not associated with asthma or atopy.

CONCLUSIONS

We found that two objective markers of folate deficiency were associated with self-reported doctor-diagnosed asthma and attacks of shortness of breath, but not with lung function or atopy.

Combined analyses of 20 common obesity susceptibility variants

OBJECTIVE

Genome-wide association studies and linkage studies have identified 20 validated genetic variants associated with obesity and/or related phenotypes. The variants are common, and they individually exhibit small-to-modest effect sizes.

RESEARCH DESIGN AND METHODS

In this study we investigate the combined effect of these variants and their ability to discriminate between normal weight and overweight/obese individuals. We applied receiver operating characteristics (ROC) curves, and estimated the area under the ROC curve (AUC) as a measure of the discriminatory ability. The analyses were performed cross-sectionally in the population-based Inter99 cohort where 1,725 normal weight, 1,519 overweight, and 681 obese individuals were successfully genotyped for all 20 variants.

RESULTS

When combining all variants, the 10% of the study participants who carried more than 22 risk-alleles showed a significant increase in probability of being both overweight with an odds ratio of 2.00 (1.47-2.72), P = 4.0 x 10(-5), and obese with an OR of 2.62 (1.76-3.92), P = 6.4 x 10(-7), compared with the 10% of the study participants who carried less than 14 risk-alleles. Discrimination ability for overweight and obesity, using the 20 single nucleotide polymorphisms (SNPs), was determined to AUCs of 0.53 and 0.58, respectively. When combining SNP data with conventional nongenetic risk factors of obesity, the discrimination ability increased to 0.64 for overweight and 0.69 for obesity. The latter is significantly higher (P < 0.001) than for the nongenetic factors alone (AUC = 0.67).

CONCLUSIONS

The discriminative value of the 20 validated common obesity variants is at present time sparse and too weak for clinical utility, however, they add to increase the discrimination ability of conventional nongenetic risk factors.

Differential relationship between physical activity and progression to diabetes by glucose tolerance status: the Inter99 Study

AIMS/HYPOTHESIS

The aim of the study was to analyse how strongly commuting and leisure-time physical activity affect progression to diabetes and to study whether this relationship is different in individuals with isolated impaired fasting glucose (i-IFG) and isolated impaired glucose tolerance (i-IGT).

METHODS

We studied the incidence of diabetes in 4,031 individuals without diabetes at baseline who participated in the baseline and 5 year follow-up examinations of a population-based primary prevention study, the Inter99 Study. Glucose tolerance status at baseline and at follow-up were based on OGTTs. Commuting and leisure-time physical activity at baseline were assessed by questionnaire. We present rate ratios from Poisson regression analyses adjusted for relevant confounders.

RESULTS

The progression rate to diabetes was lower among physically active individuals in the total study population and particularly among those with i-IGT. The associations were attenuated and lost statistical significance after further adjustment for BMI. We observed no impact of physical activity on the progression to diabetes in individuals with i-IFG.

CONCLUSIONS/INTERPRETATION

Physical activity was associated with a lower progression to diabetes in the total study population and in individuals with i-IGT, a condition primarily characterised by muscle insulin resistance. Physical activity did not predict progression to diabetes in individuals with i-IFG, a condition primarily characterised by hepatic insulin resistance. Our results suggest that there is a differential relationship between physical activity and progression to diabetes among those with i-IFG and i-IGT. Therefore, clinical trials testing the effect of physical activity on progression from i-IFG to diabetes are needed.

TRIAL REGISTRATION

ClinicalTrials.gov ID No.: NCT00289237

FUNDING

The Danish Medical Research Council, the Danish Center for Evaluation and Health Technology Assessment, Novo Nordisk, Copenhagen County, the Danish Heart Foundation, the Danish Diabetes Association, the Danish Pharmaceutical Association, the Augustinus Foundation, the Ib Henriksen Foundation and the Becket Foundation.

Lifestyle and genetic determinants of folate and vitamin B12 levels in a general adult population

Danish legislation regarding food fortification has been very restrictive resulting in few fortified food items on the Danish market. Folate and vitamin B12 deficiency is thought to be common due to inadequate intakes but little is known about the actual prevalence of low serum folate and vitamin B12 in the general population. The aim of the present study was to evaluate the folate and vitamin B12 status of Danish adults and to investigate associations between vitamin status and distinct lifestyle and genetic factors. The study included a random sample of 6784 individuals aged 30–60 years. Information on lifestyle factors was obtained by questionnaires and blood samples were analysed for serum folate and vitamin B12 concentrations and several genetic polymorphisms. The overall prevalence of low serum folate ( < 6·8 nmol/l) was 31·4 %. Low serum folate was more common among men than women and the prevalence was lower with increasing age. Low serum folate was associated with smoking, low alcohol intake, high coffee intake, unhealthy diet, and the TT genotype of the methylenetetrahydrofolate reductase (MTHFR)-C677T polymorphism. The overall prevalence of low serum vitamin B12 ( < 148 pmol/l) was 4·7 %. Low serum vitamin B12 was significantly associated with female sex, high coffee intake, low folate status, and the TT genotype of the MTHFR-C677T polymorphism. In conclusion, low serum folate was present in almost a third of the adult population in the present study and was associated with several lifestyle factors whereas low serum concentrations of vitamin B12 were less common and only found to be associated with a few lifestyle factors.

Five years of lifestyle intervention improved self-reported mental and physical health in a general population: the Inter99 study

INTRODUCTION

Self-reported health has been shown to predict mortality. We lack knowledge on whether a lifestyle intervention can improve self-reported mental and physical health in a general population.

METHODS

Inter99, Denmark (1999-2006) is a randomised population-based intervention study. We screened for ischemic heart disease and repeatedly offered advice and assistance to obtain a healthier lifestyle. Health related quality of life was measured by Short Form 12 (SF-12); completed by 9322 at baseline and 7719 at five-year follow-up. In linear mixed models we investigated the effect of the intervention on self-reported health over time.

RESULTS

At baseline men had higher physical health-component scores (PCS) than women. Living with a partner, being employed, and being healthy was associated with high PCS. The mental health-component scores (MCS) showed the same socio-demographic differences, except that MCS increased with age. Significantly fewer participants in the intervention groups had decreased their PCS and MCS compared with the control group. Adjusted multilevel analyses confirmed that the intervention significantly improved physical- (p=0.008) and mental health (p<0.001) over time compared with the control group.

CONCLUSION

Screening for ischemic heart disease and offering lifestyle intervention had a significantly beneficial effect on mental and physical self-reported health in the long term in a general population.

The impact of a population-based multi-factorial lifestyle intervention on alcohol intake: the Inter99 study

PURPOSE

To investigate the effect of screening and five years of multi-factorial lifestyle intervention on changes in alcohol intake in a general population.

METHODS

The study was a pre-randomized intervention study on lifestyle, Inter99 (1999-2006), Copenhagen, Denmark. Participants in the intervention group (n=6 091) had at baseline a medical health examination and a face-to-face lifestyle counselling. Individuals at high risk of ischemic heart disease were repeatedly offered both individual and group-based counselling. The control group (n=3 324) was followed by questionnaires. Alcohol intake was measured by questionnaires. Changes were analysed by multilevel analyses.

RESULTS

Binge drinking decreased both in men and women at three and five-year follow-ups (men: five-year: net-change:-0.13; p=0.03; women: five-year: net-change:-0.08; p=0.04). Furthermore, in women the ratio between wine and total alcohol was increased compared with the control group at five-year follow-up (net-change: 0.04; p<0.01). In men with a high intake of alcohol (>21 drinks per week) the effect on total alcohol intake was maintained at five-year follow-up (net-change: -3.7; p=0.01). No significant effects were found in women on total alcohol intake.

CONCLUSION

Multi-factorial lifestyle intervention, including low intensity alcohol intervention, improved long-term alcohol habits in a general population.

Dietary patterns predict changes in two-hour post-oral glucose tolerance test plasma glucose concentrations in middle-aged adults

We examined whether the adherence to major dietary patterns at baseline of 5824 nondiabetic Danes (30-60 y) enrolled in the nonpharmacological Inter99 intervention predicted changes in fasting plasma glucose (FPG) and postchallenge 2-h plasma glucose (2h-PG) concentrations during a 5 y period and whether a potential association was dependent on baseline glucose tolerance status. Through principal component analysis, a score for a traditional dietary pattern (characterized by higher intakes of high-fat sandwich spreads, red meat, potatoes, butter and lard, low-fat fish, sandwich meat, and sauces) and a score for a modern dietary pattern (characterized by higher intakes of vegetables, fruit, vegetable oil/vinegar dressing, poultry, pasta, rice, and cereals) were estimated for each person at baseline. Random effect models adjusting for relevant confounders were used to estimate changes in repetitive measures of FPG and 2h-PG. A higher modern score (of 1 SD) predicted an annual decrease in 2h-PG of 0.015 mmol/L (P < 0.01) regardless of glucose tolerance status. For individuals with isolated impaired glucose tolerance, a higher traditional score (of 1 SD) predicted an annual increase in 2h-PG of 0.083 mmol/L (P < 0.0001). In conclusion, glucose tolerance status did not, in general, affect the predictive effect of the dietary patterns. The study suggests that the risk of worsening 2h-PG concentrations may be smaller for individuals with a high modern dietary pattern score characterized by high intakes of vegetables, fruit, vegetable oil/vinegar dressing, poultry, pasta, rice, and cereals.

Refinement and validation of an FFQ developed to estimate macro- and micronutrient intakes in a south Indian population

Objective

Potential error sources in nutrient estimation with the FFQ include inaccurate or biased recall and overestimation or underestimation of intake due to too many or too few items on the FFQ, respectively. Here we report the refinement of an FFQ that overestimated nutrient intake and its validation against multiple 24 h recalls.

Study design

Data on 2527 participants in south India (Trivandrum) were available for the original FFQ (OFFQ) that overestimated nutrient intake (132 food items). After excluding participants with implausible energy intake estimates (<2·72 MJ/d (<650 kcal/d), >15·69 MJ/d (>3750 kcal/d)) we ran stepwise regression analyses with selected nutrients as the outcomes and food intake (servings/d) as predictor variables (n1867). From these results and expert consultation we refined the FFQ (RFFQ), and validated it by comparing intakes obtained with it and the mean of two 24 h recalls among 100 participants.

Results

The OFFQ overestimated usual daily nutrient intake before and after exclusions [for energy: 13·39 (sd5·46) MJ (3201 (sd1305) kcal) and 10·96 (sd2·65) MJ (2619 (sd634) kcal), respectively]. In stepwise analyses, fifty-seven food items explained 90 % of the variance in nutrients; we retained thirteen food items because participants consumed them at least twice monthly and twelve food items that local nutritionists recommended. Mean energy intake estimated from the RFFQ (eighty-two food items) was 7·94 (sd2·05) MJ (1897 (sd489) kcal). The de-attenuated correlations between mean 24 h recall and RFFQ intakes ranged from 0·25 (vitamin A) to 0·82 (fat).

Conclusion

We refined an FFQ that overestimated nutrient intake by shortening and redesigning, and validated it by comparisons with 24 h dietary recall data.

The effect of adding group-based counselling to individual lifestyle counselling on changes in dietary intake. The Inter99 study--a randomized controlled trial

BACKGROUND

Few studies have investigated the specific effect of single intervention components in randomized controlled trials. The purpose was to investigate the effect of adding group-based diet and exercise counselling to individual life-style counselling on long-term changes in dietary habits.

METHODS

The study was a randomized controlled intervention study. From a general Danish population, aged 30 to 60 years (n = 61,301), two random sample were drawn (group A, n = 11,708; group B, n = 1,308). Subjects were invited for a health screening program. Participation rate was 52.5%. All participants received individual life-style counselling. Individuals at high risk of ischemic heart disease in group A were furthermore offered group-based life-style counselling. The intervention was repeated for high-risk individuals after one and three years. At five-year follow-up all participants were invited for a health examination. High risk individuals were included in this study (n = 2 356) and changes in dietary intake were analyzed using multilevel linear regression analyses.

RESULTS

At one-year follow-up group A had significantly increased the unsaturated/saturated fat ratio compared to group B and in men a significantly greater decrease in saturated fat intake was found in group A compared to group B (net change: -1.13 E%; P = 0.003). No differences were found between group A and B at three-year follow-up. At five-year follow-up group A had significantly increased the unsaturated/saturated fat ratio (net change: 0.09; P = 0.01) and the fish intake compared to group B (net change: 5.4 g/day; P = 0.05). Further, in men a non-significant tendency of a greater decrease was found at five year follow-up in group A compared to group B (net change: -0.68 E%; P = 0.10). The intake of fibre and vegetables increased in both groups, however, no significant difference was found between the groups. No differences between groups were found for saturated fat intake in women.

CONCLUSION

Offering group-based counselling in addition to individual counselling resulted in small, but significantly improved dietary habits at five-year follow-up and a tendency of better maintenance, compared to individual counselling alone.

TRIAL REGISTRATION

The Inter99 study was approved by the local Ethics Committee (KA 98 155) and is registered with ClinicalTrials.gov (registration number: NCT00289237).