Minna E Similä

National Institute for Health and Welfare, Finland, Helsinki, Southern Finland Province, Finland

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Publications (10)32.02 Total impact

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    ABSTRACT: We have examined the associations between dietary glycaemic index (GI), substitutions of total, low-, medium- and high-GI carbohydrates for fat and the risk of CHD. The study consisted of 21 955 male smokers, aged 50-69 years, within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The diet was assessed at baseline using a validated FFQ. During a 19-year follow-up, 4379 CHD cases (2377 non-fatal myocardial infarctions and 2002 CHD deaths) were identified from national registers. Relative risks (RR) and CI for CHD were analysed using Cox proportional hazards modelling, and multivariate nutrient density models were applied to examine the associations between the substitutions of macronutrients and the risk of CHD. Dietary GI was inversely associated with CHD risk: multivariate RR in the highest v. lowest quintile was 0·89 (95 % CI 0·81, 0·99). Replacement of higher-GI carbohydrates with lower-GI carbohydrates did not associate with the risk. Replacing saturated and trans-fatty acids with carbohydrates was associated with decreased CHD risk: RR for substitution of 2 % of energy intake was 0·97 (95 % CI 0·94, 0·99). On the contrary, replacing MUFA with carbohydrates was associated with an increased risk: RR for substitution of 2 % of energy intake was 1·08 (95 % CI 1·01, 1·16). We conclude that in the present study population, contrary to the hypothesis, a lower GI does not associate with a decreased risk of CHD. The associations of carbohydrates with CHD risk depend on the fatty acid composition of the diet.
    The British journal of nutrition 03/2013; · 3.45 Impact Factor
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    ABSTRACT: We examined the associations between carbohydrate substitutions (total; low-, medium-, high-glycemic index (GI) carbohydrates) for fat or protein and risk of type 2 diabetes. The cohort comprised 25,943 male smokers among whom 1098 diabetes cases were identified from a national register during a 12-year follow-up. Diet was assessed by a validated food frequency questionnaire. The relative risks (RR) and confidence intervals (CI) for diabetes were analyzed using Cox proportional hazard modeling, and multivariate nutrient density models were applied to examine the associations between substitutions of macronutrients and diabetes risk. The risk of diabetes was lower when fat or protein was replaced with an isoenergetic amount (2% of energy intake) of carbohydrates, the multivariate RRs were 0.96 (95% CI: 0.94, 0.99) and 0.85 (95% CI: 0.80, 0.90), respectively. The lower risks were due to replacing saturated plus trans fatty acids, and meat, milk or plant protein with carbohydrates, respectively. Low-, medium- or high-GI carbohydrates did not associate with lower diabetes risk when replacing fat or fatty acids, except when total fat was replaced with medium-GI carbohydrates. Low-, medium- and high-GI carbohydrates had similar inverse associations with diabetes risk when they replaced total, meat or milk protein. Higher carbohydrate intake at the expense of fat, attributable to trans and saturated fatty acids, or protein was associated with decreased diabetes risk. Replacing fat or protein with lower-GI carbohydrates was not more beneficial than replacing it with higher-GI carbohydrates.
    European journal of clinical nutrition 02/2012; 66(6):716-21. · 3.07 Impact Factor
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    ABSTRACT: FFQ require validation as part of epidemiological research of diet-disease relationships. Studies exploring associations between carbohydrate type and chronic diseases are rapidly increasing, but information on the validity of carbohydrate fractions, dietary glycaemic index (GI) and the glycaemic load (GL) estimated by FFQ is scarce. Likewise, the effects of subject characteristics on FFQ validity have been poorly documented. The present study evaluates the relative validity of an 131-item FFQ in relation to two 3 d food records (FR) performed 6 months apart focusing on the intake of carbohydrate fractions, dietary GI and the GL. Furthermore, we assessed the extent to which subjects' age, education and BMI explain differences between these methods. The study sample comprised 218 men and 292 women aged 25-74 years participating in a large population-based survey in Finland. Energy-adjusted Spearman's rank correlations ranged from 0·27 (sugars) to 0·70 (lactose) for men and from 0·37 (sugars) to 0·69 (lactose) for women. On average, 73 % of the subjects were categorised into the same or adjacent distribution quintile based on the two methods. In general, the FFQ overestimated the intakes compared with FR. Especially in women, FFQ validity for some nutrients was associated with the level of intake, subjects' age and, to a lesser extent, education but not BMI. In conclusion, the FFQ appears to be reasonably valid in the assessment of carbohydrate exposure variables, but the findings show a need for adjustment of diet-disease relationships for subjects' age and education.
    The British journal of nutrition 09/2011; · 3.45 Impact Factor
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    ABSTRACT: The glycaemic index (GI) is used to describe the blood glucose-raising potential of carbohydrate-containing foods. Only a few descriptions of the addition of GI values to national food composition databases (FCDBs) exist. We tested whether the value documentation framework established within the European Food Information Resource (EuroFIR) Network could be used for GI values when adding them to the Finnish FCDB. The list of foods requiring GI values was based on the National FINDIET 2007 Survey data and extended with foods encoded in a food-frequency questionnaire used in other nationally representative studies. The minimum quality of GI measurements was verified when gathering values from various sources, using earlier defined criteria. If a measured GI value for a food was directly available, or could be imputed or estimated, the value was added to the Finnish FCDB and documented using core standard vocabularies of EuroFIR. The GI values of composite foods were calculated using recipe calculation software. A total of 2210 foods required a GI value. GI values for 1322 foods were available and added to the FCDB. The remaining 888 foods were composite foods and received a GI value through recipe calculation. The standard vocabularies describing the origin of the GI values, the methods used in their derivation and their qualitative characteristics were suitable for GI values. GI values can be added to FCDBs and documented using terms similar to those used for traditional food composition data. Standardised value documentation may provide transparency for GI database compilation processes.
    European journal of clinical nutrition 11/2010; 64 Suppl 3:S68-72. · 3.07 Impact Factor
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    ABSTRACT: Findings on dietary glycaemic index (GI) and glycaemic load (GL) as risk factors for type 2 diabetes have been controversial. We examined the associations of dietary GI and GL and the associations of substitution of lower-GI carbohydrates for higher-GI carbohydrates with diabetes risk in a cohort of Finnish men. The cohort consisted of 25 943 male smokers aged 50-69 years. Diet was assessed, at baseline, using a validated diet history questionnaire. During a 12-year follow-up, 1098 incident diabetes cases were identified from a national register. Cox proportional hazard modelling was used to estimate the risk of diabetes, and multivariate nutrient density models were used to examine the effects of substitution of different carbohydrates. Dietary GI and GL were not associated with diabetes risk; multivariate relative risk (RR) for highest v. lowest quintile for GI was 0·87 (95 % CI 0·71, 1·07) and for GL 0·88 (95 % CI 0·65, 1·17). Substitution of medium-GI carbohydrates for high-GI carbohydrates was inversely associated with diabetes risk (multivariate RR for highest v. lowest quintile 0·75, 95 % CI 0·59, 0·96), but substitution of low-GI carbohydrates for medium- or high-GI carbohydrates was not associated with the risk. In conclusion, dietary GI and GL were not associated with diabetes risk, and substitutions of lower-GI carbohydrates for higher-GI carbohydrates were not consistently associated with a lower diabetes risk. The associations of dietary GI and GL with diabetes risk should be interpreted by considering nutritional correlates, as foods may have different properties that affect risk.
    The British journal of nutrition 11/2010; 105(8):1258-64. · 3.45 Impact Factor
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    ABSTRACT: Interest in the dietary glycaemic index (GI) and glycaemic load (GL) as risk factors for chronic diseases has grown in recent years but findings have been controversial. We describe the compilation of the GI database for the cohort studies within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study and the main characteristics associating with diet GI and GL. The ATBC Study enrolled 29 133 male smokers aged 50-69 years who filled in a dietary history questionnaire upon study entry. The dietary data included 1097 foods, of which 195 foods with no or a negligible amount of available carbohydrates were assigned a GI of zero. Based on preset methodological criteria for published GI studies, the GI value of a similar food was available for 130 foods, and the GI of related food was assigned to 360 foods. The GI values of these foods served in the GI calculation of 412 composite foods. The median diet GI among the ATBC Study participants was 67.3 (interquartile range 64.8-70.0), and the median diet GL was 175 (interquartile range 158-192). The intakes of carbohydrates, protein and fat decreased, and the intake of fibre increased, with increasing GI. The GL showed a positive correlation with intakes of carbohydrates and dietary fibre and a negative correlation with intakes of protein and fat. The GI studies available that fulfilled the minimum methodological requirements cover a sufficient amount of foods to form a meaningful GI database for epidemiological study. This, however, requires the availability of GI values for relevant local carbohydrate-containing foods.
    The British journal of nutrition 10/2008; 101(9):1400-5. · 3.45 Impact Factor
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    ABSTRACT: The prevalence of obesity varies across countries. However, less is known about the geographical, within-country variation. This study investigated and visualized the geographical differences in general obesity defined by body mass index (BMI) and in abdominal obesity defined by waist circumference and waist-to-hip ratio (WHR) in Finland. Subjects and methods: Data for the study consisted of three large population surveys: Health 2000 Survey with a nationally representative sample together with the National FINRISK Study conducted in five areas in 1997 and six areas in 2002. Altogether, 17 816 men and women aged 30-64 years participated in the surveys. In each survey, subjects' weight, height and circumferences of waist and hip were measured. The geographical pattern of mean anthropometric values and obesity prevalence were studied applying a Bayesian hierarchical approach and Geographical Information Systems. Both in men and women, the prevalence of obesity (BMI >/= 30 kg m(-2)) varied little across geographical areas, but it was smaller in cities compared with other areas across the country. In men, the prevalence of abdominal obesity defined both by waist circumference and WHR was higher in western Finland compared with southern and northern Finland. Also in women, the prevalence of abdominal obesity was highest in western Finland, especially as defined by waist circumference. Geographical variation in BMI was different and less prominent than in waist circumference and WHR. Abdominal obesity was surprisingly high in western Finland, the area seldom investigated. Mapping obesity gives a useful tool for professionals working in the field of health promotion.
    The European Journal of Public Health 10/2008; 18(6):637-43. · 2.52 Impact Factor
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    ABSTRACT: To measure the validity and reproducibility of the NORBAGREEN food frequency questionnaire (FFQ). In Finland, 125 subjects aged 25-64 years sampled from the five main regions of the FINDIET 2002 Study and in Lithuania, 99 citizens of Kaunas aged 19-75 years participated in the study. Reference methods for the FFQ were two 3-day FFQs in Finland and four 24-h recalls in Lithuania. The FFQ was repeated after 6-8 months in both countries. The outcome of the FFQ1 was correlated with the outcome of the reference methods and with the outcome of repeated FFQ2. Cross-classification of food intakes by FFQ1 and the reference methods was examined in tertiles. Validity correlations (FFQ vs the reference method, Spearman's correlation) were for vegetables, fruit and bread 0.50 (P<0.01), 0.53 (P<0.01) and 0.54 (P<0.01) in Finland; and 0.55 (P<0.01), 0.31 (P<0.01) and 0.51 (P<0.01) in Lithuania, respectively. Correlations were smaller for potatoes and fish. The overall proportion categorized in the same or adjacent intake tertiles with the two instruments was over 83% in both countries. Reproducibility correlations varied between 0.51 and 0.75 in the Finnish study, and between 0.51 and 0.83 in the Lithuanian study. The NORBAGREEN FFQ can be used to rank subjects according to vegetable, fruit and bread consumption. Questions on fish and potato consumption need to be developed further.
    European journal of clinical nutrition 09/2007; 63(1):141-9. · 3.07 Impact Factor
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    ABSTRACT: Methodologic choices affect measures of the glycemic index (GI). The effects on GI values of blood sampling site, reference food type, and the number of repeat tests have been insufficiently determined. The objective was to study the effect of methodologic choices on GI values. Comparisons were made between venous and capillary blood sampling and between glucose and white bread as the reference food. The number of tests needed for the reference food was assessed. Rye bread, oatmeal porridge, and instant mashed potato were used as the test foods. Twelve healthy volunteers were served each test food once and both reference foods 3 times at 1-wk intervals in a random order after they had fasted overnight. Capillary and venous blood samples were drawn at intervals for 3 h after each study meal. GIs and their CVs based on capillary samples were lower than those based on venous samples. Two tests of glucose solution as the reference provided stable capillary GIs for the test foods. The capillary GIs did not differ significantly when white bread was used as the reference 1, 2, or 3 times, but the variation was lower when tests were performed 2 and 3 times. Capillary GIs with white bread as the reference were 1.3 times as high as those with glucose as the reference. The capillary GIs of rye bread, oatmeal porridge, and mashed potato were 77, 74, and 80, respectively, with glucose as the reference. Capillary blood sampling should be used in the measurement of GI, and reference tests with glucose or white bread should be performed at least twice.
    American Journal of Clinical Nutrition 12/2006; 84(5):1055-61. · 6.50 Impact Factor
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    ABSTRACT: Dietary pattern analysis has recently been used in nutritional epidemiology. However, there has been little research on nutrient co-occurrence patterns in foods although they are useful for understanding associations of nutrients in foods. In this study, nutrient content data of Finnish foods were submitted to factor analysis. From the food composition database Fineli®, 530 basic food items and 106 common nutrients were selected. Nutrient patterns were analysed in two data sets, nutrient values (/100 g) and nutrient densities (/1 MJ), with principal component solutions of factor analysis. Four patterns, explaining 36–39% of total variance in nutrient content, were identified for both solutions. The patterns in the nutrient value solution were characterised by: (1) fish, meat, dairy products, legumes, seeds, nuts; (2) vegetable fats; (3) staple foods; and (4) offal foods (liver, kidney). In the nutrient density solution, the patterns were characterised by: (1) vegetables and berries; (2) low fat fish, meat and dairy products; (3) mushrooms and offal foods (liver, kidney); and (4) vegetable fats. These patterns were consistent with prior knowledge of nutrient composition. The basic structures of nutrient content among foods seem to have held constant over recent decades. The study also attests to the benefit of increased consumption of vegetables, fruit and cereals.
    Journal of Food Composition and Analysis. 01/2006;