OBJECTIVE: Using a nested case-referent design, we evaluated the relationship between plasma levels of the lignan enterolactone and the risk of developing breast cancer. METHODS: 248 cases and 492 referents were selected from three population-based cohorts in northern Sweden. Blood samples were donated at enrollment. All blood samples were stored at -80 degrees C. Cases and referents were matched for age, date of blood sample and sampling centre. Breast cancer cases were identified through the regional and national cancer registries. RESULTS: Plasma enterolactone was lower among smokers in all cohorts and in subjects with BMI 28 in one of the cohorts. Low plasma concentrations of enterolactone, below the 12.5(th) percentile (mean plasma enterolactone 2.9 nmol/l), were associated with an increased risk of breast cancer. Also, high values of plasma enterolactone, above the 87.5(th) percentile (mean plasma enterolactone 58.2 nmol/l) were significantly associated with an increased breast cancer risk among women from two cohorts with only incident cases and a higher number of pre-menopausal women. High plasma enterolactone concentrations among older women from a mammary screening project with mostly prevalent cases were associated with a non-significant slightly reduced breast cancer risk. CONCLUSION: Very low plasma concentrations of enterolactone were associated with an increased breast cancer risk in all three cohorts. In two of the cohorts, with only incident cases, very high plasma concentrations were also associated with an increased breast cancer risk. In the third cohort with mainly screen-detected cases from a mammary screening program, high plasma enterolactone concentrations were associated with a weak decreased breast cancer risk.
Dietary intake of naturally occurring plant sterols is inversely related to serum cholesterol concentrations. Elevated serum cholesterol increases the risk of myocardial infarction (MI), but it is unknown if this can be reduced by dietary intake of naturally occurring plant sterols. Our aim was to investigate if a high intake of naturally occurring plant sterols is related to a lower risk of contracting a first MI. The analysis included 1005 prospective cases (219 women, 786 men) and 3148 matched referents (723 women, 2425 men), aged 29-73 y at baseline, from the population-based Northern Sweden Health and Disease Study. A food frequency questionnaire (FFQ) was completed at baseline. Absolute plant sterol intake was inversely related to the risk of a first MI in men (OR highest vs. lowest quartile = 0.70; 95% CI: 0.53, 0.85; P-trend = 0.006) but not in women. After adjustment for confounders, the estimated risk was somewhat attenuated (OR highest vs. lowest quartile = 0.71; 95% CI: 0.55, 0.92; P-trend = 0.067), suggesting that increasing sterol intake from 150 to 340 mg/d reduces the risk of a first MI by 29%. Energy-adjusted plant sterol intake was not related to the risk of a first MI in either men or women. In conclusion, the findings of this observational study show that a high absolute intake of naturally occurring plant sterols is significantly related to a lower risk of a first MI in men in northern Sweden, whereas no significant relation was seen for energy-adjusted plant sterol intake. In women, no significant associations were found. The results from this study show that intake of plant sterols may be important in prevention of MI.
Department of Internal Medicine and Clinical Nutrition, Institution of Medicine, Sahlgrenska Academy at University of Gothenburg, P.O. Box 459, SE-405 30 Göteborg, Sweden. firstname.lastname@example.org
To evaluate plant sterol intake estimated with the eighty-four-item Northern Sweden FFQ against repeated 24 h dietary recalls (24-HDR) as the reference method.
Randomly recruited participants from the Västerbotten Intervention Programme (VIP) responded to an FFQ (FFQ1). Over the subsequent 12 months, ten repeated 24-HDR were carried out. After this, a second FFQ (FFQ2) was completed.
Västerbotten county, northern Sweden.
Ninety-six men and ninety-nine women.
The Pearson correlation coefficient for absolute total plant sterol intake estimated with FFQ1 and 24-HDR was 0.58 and 0.55 for the men and women, respectively. Cross-classification of participants into quartiles of absolute plant sterol intake estimated with FFQ1 and 24-HDR showed that 90% of the men and 83% of the women were classified into the same or an adjacent quartile. For energy-adjusted plant sterol intake, 71% of the men and 74% of the women were classified into the same or an adjacent quartile. The agreement for cross-classification of participants into quartiles between FFQ1 and FFQ2 was good for both absolute and energy-adjusted plant sterol intake.
The FFQ is able to capture absolute plant sterol intake to the same extent as other nutrients, and to rank individuals according to both their absolute and energy-adjusted plant sterol intake. The reproducibility of the FFQ was good, suggesting that the method is reliable. This makes it possible to use plant sterol data from the FFQ in large-scale studies of the association between plant sterol intake and disease.
Dietary patterns capture the overall diet and thereby provide information on how nutrients are consumed in combinations, and have been suggested to be a better method than studying single nutrients. The present study explored the relationship between dietary patterns at baseline and incidence of obesity at 10-year follow-up in women.
A longitudinal study using baseline measurements from 1992-1996, including food intake, medication, heredity, socio-economic status, lifestyle and measured body composition, and follow-up data collected in 2002-2006 including measured body composition.
Data from the Västerbotten Intervention Programme (VIP) in Sweden.
A total of 6545 initially non-obese women aged 30-50 years.
Among women reporting plausible energy intakes, the 'Fruit and vegetables cluster' predicted the highest incidence of obesity (OR = 1·76, 95 % CI 1·11, 2·76; P = 0·015) compared with women in the other food pattern groups combined. When adjusting for metabolic factors and BMI at baseline, the risk for obesity in the 'Fruit and vegetables cluster' was attenuated to non-significance. In contrast, high intake of fruit per se was associated with a decreased risk of developing obesity (OR = 0·69, 95 % CI 0·51, 0·91; P = 0·010).
Dietary pattern groups identified by cluster analysis are likely to reflect characteristics in addition to diet, including lifestyle, previous and current health status and risk factors for future disease, whereas intake of fruit per se was a stable indicator and less affected by baseline characteristics. These results underscore the need for complementary methods in understanding diet-disease relationships.
BACKGROUND AND PURPOSE: Folate metabolism has been implicated in stroke. However, the possibility of a role for folate and vitamin B12, independent of their effects on homocysteine status, remains to be explored. The aim of this prospective, nested case-referent study was to relate plasma and dietary intake levels of folate and vitamin B12 to risk of stroke, taking into consideration plasma homocysteine concentrations and methylenetetrahydrofolate reductase polymorphisms. METHODS: Subjects were 334 ischemic and 62 hemorrhagic stroke cases and matched double referents from the population-based Northern Sweden Health and Disease Cohort. RESULTS: Plasma folate was statistically significantly associated with risk of hemorrhagic stroke in an inverse linear manner, both in univariate analysis and after adjustment for conventional risk factors including hypertension (odds ratio [OR] for highest versus lowest quartile 0.21 (95% confidence interval [CI], 0.06 to 0.71; P for trend=0.008)). Risk estimates were attenuated by inclusion of homocysteine in the model (OR, 0.34; 95% CI, 0.08 to 1.40; P for trend=0.088). A similar pattern was observed for increasing folate intake (multivariate OR, 0.07; 95% CI, 0.01 to 0.55; P for trend=0.031 without homocysteine, and OR, 0.16, 95% CI, 0.02 to 1.23; P for trend=0.118 with homocysteine in the analysis). We found little evidence of an association between plasma or dietary folate and risk of ischemic stroke. Neither plasma nor dietary vitamin B12 was associated with risk of either stroke subtype. CONCLUSIONS: The results of this study suggest a protective role for folate, possibly in addition to its effects on homocysteine status, in hemorrhagic but not ischemic stroke.
Although carbohydrate reduction of varying degrees is a popular and controversial dietary trend, potential long-term effects for health, and cancer in specific, are largely unknown.
We studied a previously established low-carbohydrate, high-protein (LCHP) score in relation to the incidence of cancer and specific cancer types in a population-based cohort in northern Sweden. Participants were 62,582 men and women with up to 17.8 years of follow-up (median 9.7), including 3,059 prospective cancer cases. Cox regression analyses were performed for a LCHP score based on the sum of energy-adjusted deciles of carbohydrate (descending) and protein (ascending) intake labeled 1 to 10, with higher scores representing a diet lower in carbohydrates and higher in protein. Important potential confounders were accounted for, and the role of metabolic risk profile, macronutrient quality including saturated fat intake, and adequacy of energy intake reporting was explored.
For the lowest to highest LCHP scores, 2 to 20, carbohydrate intakes ranged from median 60.9 to 38.9% of total energy intake. Both protein (primarily animal sources) and particularly fat (both saturated and unsaturated) intakes increased with increasing LCHP scores. LCHP score was not related to cancer risk, except for a non-dose-dependent, positive association for respiratory tract cancer that was statistically significant in men. The multivariate hazard ratio for medium (9-13) versus low (2-8) LCHP scores was 1.84 (95% confidence interval: 1.05-3.23; p-trend?=?0.38). Other analyses were largely consistent with the main results, although LCHP score was associated with colorectal cancer risk inversely in women with high saturated fat intakes, and positively in men with higher LCHP scores based on vegetable protein.
These largely null results provide important information concerning the long-term safety of moderate carbohydrate reduction and consequent increases in protein and, in this cohort, especially fat intakes. In order to determine the effects of stricter carbohydrate restriction, further studies encompassing a wider range of macronutrient intakes are warranted.
The Mediterranean diet has been widely promoted and may be associated with chronic disease prevention and a better overall health status. The aim of this study was to evaluate whether the Mediterranean diet score inversely predicted total or cause-specific mortality in a prospective population study in Northern Sweden (Västerbotten Intervention Program). The analyses were performed in 77,151 participants (whose diet was measured by means of a validated FFQ) by Cox proportional hazard models adjusted for several potential confounders. The Mediterranean diet score was inversely associated with all-cause mortality in men [HR = 0.96 (95% CI = 0.93, 0.99)] and women [HR = 0.95 (95% CI = 0.91, 0.99)], although not in obese men. In men, but not in women, the score was inversely associated with total cancer mortality [HR = 0.92 (95% CI = 0.87, 0.98)], particularly for pancreas cancer [HR = 0.82 (95% CI = 0.68, 0.99)]. Cardiovascular mortality was inversely associated with diet only in women [HR = 0.90 (95% CI = 0.82, 0.99)]. Except for alcohol [HR = 0.83 (95% CI = 0.76, 0.90)] and fruit intake [HR = 0.90 (95% CI = 0.83, 0.98)], no food item of the Mediterranean diet score independently predicted mortality. Higher scores were associated with increasing age, education, and physical activity. Moreover, healthful dietary and lifestyle-related factors additively decreased the mortality likelihood. Even in a subarctic region, increasing Mediterranean diet scores were associated with a longer life, although the protective effect of diet was of small magnitude compared with other healthful dietary and lifestyle-related factors examined.
Food pattern analyses are popular tools in the study of associations between diet and health. However, there is a need for further evaluation of this methodology. The aim of the present cross-sectional study was to evaluate the relationship between food pattern groups (FPG) and existing health, and to identify factors influencing this relationship.
The inhabitants of Västerbotten County in northern Sweden are invited to health check-ups when they turn 30, 40, 50, and 60 years of age. The present study includes data collected from almost 60,000 individuals between 1992 and 2005. Associations between FPG (established using K-means cluster analyses) and health were analyzed separately in men and women.
The health status of the participants and their close family and reporting accuracy differed significantly between men and women and among FPG. Crude regression analyses, with the high fat FPG as reference, showed increased risks for several health outcomes for all other FPGs in both sexes. However, when limiting analysis to individuals without previous ill-health and with adequate energy intake reports, most of the risks instead showed a trend towards protective effects.
Food pattern classifications reflect both eating habits and other own and family health related factors, a finding important to remember and to adjust for before singling out the diet as a primary cause for present and future health problems. Appropriate exclusions are suggested to avoid biases and attenuated associations in nutrition epidemiology.
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Abstract Background: Abnormalities in homocysteine metabolism have been suggested as risk factors for stroke. The aim of this prospective study was to examine whether total plasma homocysteine concentration (tHcy) and its main genetic determinant, methylene tetrahydrofolate reductase (MTHFR) polymorphisms, were associated with first ischemic or hemorrhagic stroke. Methods: This was a nested case-referent study of 321 ischemic and 60 hemorrhagic stroke cases, defined by WHO MONICA criteria and each matched with two event-free referents for sex, age, cohort, recruitment date and geographical area. All subjects were from the population-based Northern Sweden Health and Disease Study cohorts. Odds ratios were determined by conditional logistic regression. Results: The mean follow-up time was 4.2 years. Both tHcy and MTHFR were independent predictors of hemorrhagic stroke in multivariate models including body mass index, hypertension and, for MTHFR, tHcy [OR for the highest vs. lowest tHcy quartile 8.13 (95% CI 1.83-36.1), p(trend)=0.002; OR for MTHFR 677TT vs. 677CC genotype 3.62 (95% CI 0.77-17.0), p(trend)=0.040]. Haplotype analyses confirmed that the MTHFR 677T-1298A haplotype was positively associated with hemorrhagic stroke [OR 1.81 (95% CI 1.09-3.00), p=0.022], whereas the MTHFR 677C-1298C haplotype was not significantly related to either hemorrhagic or ischemic stroke. Neither tHcy nor the MTHFR polymorphisms were significant predictors of ischemic stroke. Conclusion: Both elevated plasma homocysteine levels and the MTHFR 677T allele are indicators of increased risk of hemorrhagic stroke in the northern Swedish population.