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Biomedical subjects

Matti Uusitupa

Publications and source records attributed to Matti Uusitupa.

At least 19 recordsLinked to original sources

No observed local immunological response at cell level after five years of oats in adult coeliac disease.

OBJECTIVE: Our earlier 5-year follow-up study produced the first evidence to show the long-term safety of oats as part of a coeliac diet. The objective of the present study was to clarify its applicability by analysing local cellular immunological responses after 5 years' consumption of oats by adult coeliac patients. MATERIAL AND METHODS: Forty-two coeliac patients took part in an earlier oats intervention study for 6-12 months. Twenty-two of these patients originally consumed oats as part of their gluten-free diet. During the 5-year follow-up 10 patients had felt uncertain about the safety of long-term consumption of oats and gave up this part of their diet. Finally, 12 of the 22 patients consumed oats for the whole 5-year period. The control group consisted of the remaining 20 coeliac patients using a strict, conventional, gluten-free diet without oats. Intraepithelial CD3, alphabetaTCR (alphabetaIEL) and gammadeltaTCR (gammadeltaIEL) T cells were counted after specific staining of small intestinal biopsy specimens. RESULTS: There were no differences in the densities of CD3, alphabetaIEL and gammadeltaIEL T cells between the oat and the control groups. CONCLUSIONS: Long-term use of oats included in the gluten-free diets of patients with coeliac disease does not stimulate an immunological response locally in the mucosa of the small intestine.

Adult↗

Fish oil, insulin sensitivity, insulin secretion and glucose tolerance in healthy people: is there any effect of fish oil supplementation in relation to the type of background diet and habitual dietary intake of n-6 and n-3 fatty acids?

AIM: To evaluate whether a moderate supplementation of long-chain n-3 fatty acids is able to modulate insulin sensitivity, insulin secretion, beta-cell function and glucose tolerance in healthy individuals consuming a diet rich in either saturated or monounsaturated fat, also in relation to their habitual dietary intake of n-6 and n-3 fatty acid. METHODS AND RESULTS: One hundred and sixty-two healthy individuals were randomly assigned to follow either one of two isoenergetic diets for 3 months, one rich in monounsaturated fats and the other rich in saturated fats. Within each group there was a second randomisation to fish oil (n-3 fatty acids 3.6 g/day) or placebo. At the beginning and at the end of the treatment periods insulin sensitivity (SI), first phase insulin response (FPIR) and glucose tolerance (K(G)-value) were evaluated by the intravenous glucose tolerance test (IVGTT). Fish oil did not have any effect on SI, FPIR, K(G)-value and disposition index in either diet. Even after dividing subjects according to the median value of n-6/n-3 ratio of serum phospholipids at baseline, there was no change in SI (Delta SI 0.42+/-0.34 on fish oil vs 0.14+/-0.23 on placebo for those with n-6/n-3 <4.85; -1.03+/-0.47 on fish oil vs -0.27+/-0.32 on placebo for those with n-6/n-3 >4.85) (M+/-SE), FPIR (Delta FPIR 135.9+/-78.9 vs 157.2+/-157.5 pmol/L; 38.8+/-181.7 vs 357.1+/-181.7 pmol/L), K(G)-value (Delta K(G) 0.14+/-0.15 vs 0.12+/-0.11; -0.32+/-0.16 vs 0.15+/-0.15) or disposition index (Delta disposition index 1465.4+/-830.4 vs 953.8+/-690.0; -1641.6+/-1034.3 vs 446.6+/-905.1). Considering the 75th percentile of n-6/n-3 ratio (5.82) the results on insulin sensitivity, insulin secretion and disposition index were confirmed, while, in this more extreme situation, n-3 fatty acid supplementation induced a significant deterioration of K(G)-value (p=0.02). CONCLUSIONS: In healthy individuals a moderate supplementation of fish oil does not affect insulin sensitivity, insulin secretion, beta-cell function or glucose tolerance. The same is true even when the habitual dietary intake of n-6 and n-3 fatty acids is taken into account.

Adult↗

Sustained reduction in the incidence of type 2 diabetes by lifestyle intervention: follow-up of the Finnish Diabetes Prevention Study.

BACKGROUND: Lifestyle interventions can prevent the deterioration of impaired glucose tolerance to manifest type 2 diabetes, at least as long as the intervention continues. In the extended follow-up of the Finnish Diabetes Prevention Study, we assessed the extent to which the originally-achieved lifestyle changes and risk reduction remain after discontinuation of active counselling. METHODS: Overweight, middle-aged men (n=172) and women (n=350) with impaired glucose tolerance were randomly assigned to intensive lifestyle intervention or control group. After a median of 4 years of active intervention period, participants who were still free of diabetes were further followed up for a median of 3 years, with median total follow-up of 7 years. Diabetes incidence, bodyweight, physical activity, and dietary intakes of fat, saturated fat, and fibre were measured. FINDINGS: During the total follow-up, the incidence of type 2 diabetes was 4.3 and 7.4 per 100 person-years in the intervention and control group, respectively (log-rank test p=0.0001), indicating 43% reduction in relative risk. The risk reduction was related to the success in achieving the intervention goals of weight loss, reduced intake of total and saturated fat and increased intake of dietary fibre, and increased physical activity. Beneficial lifestyle changes achieved by participants in the intervention group were maintained after the discontinuation of the intervention, and the corresponding incidence rates during the post-intervention follow-up were 4.6 and 7.2 (p=0.0401), indicating 36% reduction in relative risk. INTERPRETATION: Lifestyle intervention in people at high risk for type 2 diabetes resulted in sustained lifestyle changes and a reduction in diabetes incidence, which remained after the individual lifestyle counselling was stopped.

Blood Glucose↗

CYP1A1 and CYP1B1 genetic polymorphisms, smoking and breast cancer risk in a Finnish Caucasian population.

We investigated the associations between two CYP1A1 polymorphisms (Ile462Val and Thr461Asn) and one CYP1B1 polymorphism (Leu432Val) and breast cancer risk. The study population consisted of 483 breast cancer patients and 482 healthy population controls, all of homogenous Finnish origin. No statistically significant overall associations were found between the CYP1A1 and CYP1B1 genotypes and breast cancer risk. However, a significant increase in the breast cancer risk was seen for women who had smoked 1-9 cigarettes/day and carried the CYP1B1 432Val allele; the OR was 2.6 (95% CI 1.07-6.46) for women carrying the Leu/Val genotype and 5.1 (95% CI 1.30-19.89, P for trend 0.005) for women with the Val/Val genotype compared to similarly smoking women homozygous for the 432Leu allele. Furthermore, when CYP1B1 genotypes were combined with the previously analyzed N-acetyl transferase (NAT2) genotypes, a significant increase in breast cancer risk was found among women who had at least one CYP1B1 432Val allele together with the NAT2 slow acetylator genotype (OR 1.52; 95% CI 1.03-2.24) compared to women carrying a combination of CYP1B1 Leu/Leu and NAT2 rapid acetylator genotypes. This risk was seen to be confined to ever smokers; the OR was 2.46 (95% CI 1.11-5.45) for ever smokers carrying at least one CYP1B1 432Val allele together with the NAT2 slow acetylator genotype compared to ever smokers with the CYP1B1 Leu/Leu and NAT2 rapid acetylator genotype combination. Our results suggest that the CYP1B1 polymorphism may be an important modifier of breast cancer risk in Finnish Caucasian women who have been exposed to tobacco smoke and/or carry the NAT2 slow acetylator genotype.

Adult↗

Refinement of the 22q12-q13 breast cancer--associated region: evidence of TMPRSS6 as a candidate gene in an eastern Finnish population.

Although many risk factors for breast cancer are known, most of the genetic background and molecular mechanisms still remain to be elucidated. We have previously published an autosome-wide microsatellite scan for breast cancer association and here we report a follow-up study for one of the detected regions. Ten single nucleotide polymorphisms (SNP) were genotyped in an Eastern Finnish population sample of 497 breast cancer cases and 458 controls to refine the 550-kb region on 22q12-q13 and identify the breast cancer-associated gene(s) in this region. We also studied 22q12-q13 for allelic imbalance for the detection of a possible tumor suppressor gene and to see whether the breast cancer association and allelic imbalance in this region could be connected. A SNP (rs733655) in matriptase-2 gene (TMPRSS6) was detected to associate with breast cancer risk. The genotype frequencies of rs733655 differed significantly between cases and controls in the entire sample and in the geographically and genetically more homogeneous subsample with P = 0.044 and P = 0.0003, respectively. The heterozygous genotype TC was observed to be the risk genotype in both samples (odds ratios, 1.39; 95% confidence intervals, 1.06-1.83 and odds ratios, 2.11; 95% confidence intervals, 1.46-3.05). An associated two-marker haplotype involving SNP rs733655 (empirical P = 0.041) provides further evidence for breast cancer risk factor locating on 22q12-q13, possibly being TMPRSS6. Our results suggest that matriptase-2 gene is associated with breast cancer risk in the Eastern Finnish population.

Allelic Imbalance↗

Effects of dietary saturated, monounsaturated, and n-3 fatty acids on blood pressure in healthy subjects.

BACKGROUND: The quantity and quality of fats consumed in the diet influence the risk of cardiovascular disease (CVD). Although the effect of diet on plasma lipids and lipoproteins is well documented, less information exists on the role of fats on blood pressure (BP). OBJECTIVE: The objective was to evaluate the effects of different types of dietary fat on BP in healthy subjects. DESIGN: Healthy subjects (n = 162) were randomly assigned for 3 mo to follow 1 of 2 isoenergetic diets: 1 rich in monounsaturated fatty acids (MUFA diet) and the other rich in saturated fatty acids (SFA diet). Each group was further randomly assigned to receive supplementation with fish oil (3.6 g n-3 fatty acids/d) or placebo. RESULTS: Systolic BP (SBP) and diastolic BP (DBP) decreased with the MUFA diet [-2.2% (P = 0.009) and -3.8% (P = 0.0001), respectively] but did not change with the SFA diet [-1.0% (P = 0.2084) and -1.1% (P = 0.2116)]. The MUFA diet caused a significantly lower DBP than did the SFA diet (P = 0.0475). Interestingly, the favorable effects of MUFA on DBP disappeared at a total fat intake above the median (>37% of energy). The addition of n-3 fatty acids influenced neither SBP nor DBP. CONCLUSIONS: Changing the proportions of dietary fat by decreasing SFAs and increasing MUFAs decreased diastolic BP. Interestingly, the beneficial effect on BP induced by fat quality was negated by the consumption of a high total fat intake. The addition of n-3 fatty acids to the diet had no significant effect on BP.

Adult↗

Orally administered betaine has an acute and dose-dependent effect on serum betaine and plasma homocysteine concentrations in healthy humans.

Betaine, i.e., trimethylglycine, is linked to homocysteine metabolism. A 3-mo daily betaine supplementation decreased even normal plasma total homocysteine (tHcy) concentrations in humans. The pharmacokinetic characteristics and metabolism of betaine in humans have not been investigated in detail. The aim of this study was to assess the pharmacokinetics of orally administered betaine and its acute effect on plasma tHcy concentrations. Healthy volunteers (n = 10; 3 men, 7 women) with normal body weight (mean +/- SD, 69.5 +/- 17.0 kg), 40.8 +/- 12.4 y old, participated in the study. The betaine doses were 1, 3, and 6 g. The doses were mixed with 150 mL of orange juice and ingested after a 12-h overnight fast by each volunteer according to a randomized double-blind crossover design. Blood samples were drawn for 24 h and a 24-h urine collection was performed. Orally administered betaine had an immediate and dose-dependent effect on serum betaine concentration. Single doses of 3 and 6 g lowered plasma tHcy concentrations (P = 0.019 and P < 0.001, respectively), unlike the 1-g dose. After the highest dose, the concentrations remained low during the 24 h of monitoring. The change in plasma tHcy concentration was linearly associated with betaine dose (P = 0.006) and serum betaine concentration (R2 = 0.17, P = 0.025). The absorption and elimination of betaine were dose dependent. The urinary excretion of betaine seemed to increase with an increasing betaine dose, although a very small proportion of ingested betaine was excreted via urine. In conclusion, a single dose of orally administered betaine had an acute and dose-dependent effect on serum betaine concentration and resulted in lowered plasma tHcy concentrations within 2 h in healthy subjects.

Administration, Oral↗

Dietary (n-3) fatty acids reduce plasma F2-isoprostanes but not prostaglandin F2alpha in healthy humans.

(n-3) Fatty acids are unsaturated and are therefore easily subject to oxidization; however, they have several beneficial health effects, which include protection against cardiovascular diseases. The aim of this study was to investigate whether (n-3) fatty acids, with a controlled fat quality in the background diet, affect nonenzymatic and enzymatic lipid peroxidation and antioxidant status in humans. A total of 162 men and women in a multicenter study (The KANWU study) were randomly assigned to a diet containing a high proportion of saturated fatty acids or monounsaturated fatty acids (MUFA) for 3 mo. Within each diet group, there was a second random assignment to supplementation with fish-oil capsules [3.6 g (n-3) fatty acids/d] or placebo. Biomarkers of nonenzymatic and enzymatic lipid peroxidation in vivo were determined by measuring 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) and prostaglandin F(2alpha) (PGF(2alpha)) concentrations in plasma at baseline and after 3 mo. Antioxidant status was determined by measuring plasma antioxidant capacity with an enhanced chemiluminescence assay. The plasma 8-iso-PGF(2alpha) concentration was significantly decreased after 3 mo of supplementation with (n-3) fatty acids (P = 0.015), whereas the PGF(2alpha) concentration was not affected. The antioxidant status was not affected by supplementation of (n-3) fatty acids, but was improved by the background diet with a high proportion of MUFA. We conclude that supplementation with (n-3) fatty acids decreases nonenzymatic free radical-catalyzed isoprostane formation, but does not affect cyclooxygenase-mediated prostaglandin formation.

Administration, Oral↗

Systemic immune mediators and lifestyle changes in the prevention of type 2 diabetes: results from the Finnish Diabetes Prevention Study.

The Finnish DPS (Diabetes Prevention Study) demonstrated that lifestyle intervention, aimed at increasing physical activity, improving diet, and decreasing body weight, reduced the incidence of type 2 diabetes in individuals with overweight and impaired glucose tolerance by 58%. Here, we studied which immunological markers at baseline predicted subsequent type 2 diabetes and whether there are immunologically defined subsets of subjects who are more or less responsive to the protective effects of lifestyle intervention. We randomly assigned 522 participants to a control group (n = 257) or a lifestyle intervention group (n = 265). Immunological parameters at baseline included high-sensitivity C-reactive protein (CRP), serum amyloid A, interleukin-6, regulated on activation normal T-cell expressed and secreted (RANTES), macrophage migration inhibitory factor (MIF), and soluble intercellular adhesion molecule. In the control group, CRP was the best immunological predictor for progression to overt type 2 diabetes. In the intervention group, progression to type 2 diabetes was significantly higher in subjects with the highest RANTES concentrations and was lower in subjects with the highest MIF levels. Ratios of RANTES to MIF in the upper tertile were highly predictive of incident type 2 diabetes in the intervention group (P = 0.006), whereas the association was less pronounced in the control group (P = 0.088). Thus, systemic concentrations of immune mediators appear to be associated with the progression to type 2 diabetes and the prevention of type 2 diabetes by lifestyle changes.

Anthropometry↗

XRCC1 and XPD genetic polymorphisms, smoking and breast cancer risk in a Finnish case-control study.

INTRODUCTION: It has been suggested that individuals with reduced DNA repair capacities might have increased susceptibility to environmentally induced cancer. In this study, we evaluated if polymorphisms in DNA repair genes XRCC1 (Arg280His, Arg399Gln) and XPD (Lys751Gln) modify individual breast cancer risk, with emphasis on tobacco smoking. METHODS: The study population consisted of 483 incident breast cancer cases and 482 population controls of Finnish Caucasian origin. The genotypes were determined by PCR-RFLP-based methods. Odds ratio (OR) and confidence intervals (CIs) were calculated by unconditional logistic regression analyses. RESULTS: No statistically significant overall effect in the breast cancer risk was seen for any of the studied polymorphisms. However, a significant increase in breast cancer risk was seen among ever smoking women if they carried at least one XRCC1-399 Gln allele (OR 2.33, 95% CI 1.30-4.19, pint 0.025) or XPD-751 Gln/Gln genotype (OR 2.52, 95% CI 1.27-5.03, pint 0.011) compared to smoking women not carrying these genotypes. The risks were found to be confined to women smoking at least five pack-years; the respective ORs were 4.14 (95% CI 1.66-10.3) and 4.41 (95% CI 1.62-12.0). Moreover, a significant trend of increasing risk with increasing number of the putative at-risk genotypes (p for trend 0.042) was seen. Women with at least two at-risk genotypes had an OR of 1.54 (95% CI 1.00-2.41) compared to women with no at-risk genotypes. Even higher estimates were seen for ever actively smoking women with at least two at-risk genotypes. CONCLUSION: Our results do not indicate a major role for XRCC1 and XPD polymorphisms in breast cancer susceptibility, but suggest that they may modify the risk especially among smoking women.

Adult↗

NAT2 slow acetylator genotype as an important modifier of breast cancer risk.

N-acetyltransferase 2 (NAT2) is a polymorphic enzyme participating in the metabolism of numerous pharmaceutical drugs and carcinogens found in tobacco smoke and diet. The NAT2 gene is highly polymorphic and several different allelic variants exist that determine the acetylator phenotype. In the course of our case-control study, we developed a new method based on fluorogenic allele-specific probes for analyzing the C282T and T341C polymorphisms of the NAT2 gene in 483 Finnish breast cancer patients and 482 healthy population controls. The slow NAT2 acetylation capacity-associated genotypes posed a somewhat increased overall breast cancer risk (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.01-1.73). This association was found to be confined to the advanced (stage III or IV) breast cancer (OR, 2.60; 95% CI, 1.29-5.24). When stratified by smoking habits, women who had smoked <5 pack-years and carried a NAT2 slow acetylator genotype were at a 2.6-fold (OR, 2.55; 95% CI, 1.01-6.48) risk of breast cancer. Moreover, women with the NAT2 slow acetylator genotype and low body mass index (BMI) (<25.4 kg/m2) were at somewhat increased risk of this malignancy (OR, 1.60; 95% CI, 1.07-2.39). Our results therefore suggest that NAT2 slow acetylator genotype may be an important modifier of environmentally induced breast cancer risk in Finnish women.

Adult↗

Gene-diet interaction in relation to the prevention of obesity and type 2 diabetes: evidence from the Finnish Diabetes Prevention Study.

Both genetic and environmental factors are involved in the pathogenesis of obesity and type 2 diabetes. Most of the genetic studies on common obesity are confined to the links between a given gene polymorphism or gene loci and different phenotypes of obesity or anthropometric measures. Some studies indicate that genetic factors modify the weight reduction response to energy restriction or weight gain in the long-term. Only a few studies have focused on gene-diet interaction in the development of type 2 diabetes. The Finnish Diabetes Prevention Study shows (DPS) that the success of a lifestyle intervention depends also on the polymorphisms of those genes, which are suggested to play a role in energy metabolism, lipid metabolism, insulin resistance or insulin secretion. This review deals with selected genes examined so far in the DPS.

Diabetes Mellitus, Type 2↗

Sulfotransferase 1A1 genotype as a potential modifier of breast cancer risk among premenopausal women.

SULT1A1 is involved in biotransformation of many endogenous and exogenous substrates, such as drugs, hormones and tobacco smoke carcinogens. A polymorphism in the sulfotransferase 1A1 gene (SULT1A1) results in an amino acid change from Arg to His at codon 213. The His allele (SULT1A1*2) has been shown to encode a protein with much lower catalytic activity than the protein encoded by the Arg allele (SULT1A1*1). We examined whether this polymorphism modified breast cancer risk in a Finnish-Caucasian study population consisting of 483 breast cancer patients and 482 healthy population controls. No significant genotype effects were seen in the overall breast cancer risk. However, a decreased risk of breast cancer was found among premenopausal women with at least three pregnancies and at least one SULT1A1*2 allele (odds ratio = 0.23, 95% confidence interval = 0.09-0.63) compared to women with two SULT1A1*1 alleles. Our results suggest that the SULT1A1 genotype is not an important risk factor for breast cancer in general, but may modify the risk among premenopausaul women with high parity.

Adolescent↗

Subtle hyperproinsulinaemia characterises the defective insulin secretory capacity in offspring of glutamic acid decarboxylase antibody-positive patients with latent autoimmune diabetes mellitus in adults.

OBJECTIVE: We set out to assess whether hyperproinsulinaemia is an early finding in latent autoimmune diabetes in adults (LADA). RESEARCH DESIGN AND METHODS: We measured plasma proinsulin and C-peptide responses during a 2-h oral glucose tolerance test (OGTT) and in the hyperglycaemic clamp in 21 normoglycaemic offspring of LADA patients testing positive for glutamic acid decarboxylase antibodies (GADA) or islet cell antibodies (ICA), and in 17 healthy control subjects without a family history of diabetes. RESULTS: The study groups had comparable areas under the curves of blood glucose, plasma proinsulin, C-peptide and proinsulin/C-peptide in the OGTT. However, the offspring of LADA patients had higher proinsulin/C-peptide in the hyperglycaemic clamp (P < 0.01 versus the control group). The offspring of GADA-positive LADA patients (n = 9) had higher proinsulin and proinsulin/C-peptide than did the control group in the OGTT (P < 0.05 for both comparisons) and in the hyperglycaemic clamp (P < 0.001 and P < 0.05 respectively). They also had higher proinsulin than the offspring of ICA-positive LADA patients (n = 12) (P < 0.001) in the hyperglycaemic clamp. The offspring of ICA-positive LADA patients did not clearly show hyperproinsulinaemia during the tests, but they had lower maximal glucose-stimulated insulin secretory capacity than the control group (P < 0.05) and the offspring of GADA-positive LADA patients (P < 0.05) in the hyperglycaemic clamp. CONCLUSIONS: These results suggested that insulin secretion in the offspring of GADA-positive LADA patients is characterised by subtle defects in the processing of insulin precursors. Furthermore, various proinsulin responses among the offspring of LADA patients with different autoimmune markers provided further evidence that LADA is a heterogeneous disorder.

Adult↗

Physical activity in the prevention of type 2 diabetes: the Finnish diabetes prevention study.

Clinical trials have demonstrated that lifestyle changes can prevent type 2 diabetes, but the importance of leisure-time physical activity (LTPA) is still unclear. We carried out post hoc analyses on the role of LTPA in preventing type 2 diabetes in 487 men and women with impaired glucose tolerance who had completed 12-month LTPA questionnaires. The subjects were participants in the Finnish Diabetes Prevention Study, a randomized controlled trial of lifestyle changes including diet, weight loss, and LTPA. There were 107 new cases of diabetes during the 4.1-year follow-up period. Individuals who increased moderate-to-vigorous LTPA or strenuous, structured LTPA the most were 63-65% less likely to develop diabetes. Adjustment for changes in diet and body weight during the study attenuated the association somewhat (upper versus lower third: moderate-to-vigorous LTPA, relative risk 0.51, 95% CI 0.26-0.97; strenuous, structured LTPA, 0.63, 0.35-1.13). Low-intensity and lifestyle LTPA and walking also conferred benefits, consistent with the finding that the change in total LTPA (upper versus lower third: 0.34, 0.19-0.62) was the most strongly associated with incident diabetes. Thus increasing physical activity may substantially reduce the incidence of type 2 diabetes in high-risk individuals.

Diabetes Mellitus, Type 2↗

Polymorphisms in the SLC2A2 (GLUT2) gene are associated with the conversion from impaired glucose tolerance to type 2 diabetes: the Finnish Diabetes Prevention Study.

Impaired insulin secretion is a fundamental defect in type 2 diabetes. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) in the genes regulating insulin secretion (SLC2A2 [encoding GLUT2], GCK, TCF1 [encoding HNF-1alpha], HNF4A, GIP, and GLP1R) are associated with the conversion from impaired glucose tolerance (IGT) to type 2 diabetes in participants of the Finnish Diabetes Prevention Study. With the exception of SLC2A2, other genes were not associated with the risk of type 2 diabetes. All four SNPs of SLC2A2 predicted the conversion to diabetes, and rs5393 (AA genotype) increased the risk of type 2 diabetes in the entire study population by threefold (odds ratio 3.04, 95% CI 1.34-6.88, P = 0.008). The risk for type 2 diabetes in the AA genotype carriers was increased in the control group (5.56 [1.78-17.39], P = 0.003) but not in the intervention group. We conclude that the SNPs of SLC2A2 predict the conversion to diabetes in obese subjects with IGT.

Analysis of Variance↗

An autosome-wide scan for linkage disequilibrium-based association in sporadic breast cancer cases in eastern Finland: three candidate regions found.

Breast cancer is the most common of cancers among women in industrialized countries. Many of breast cancer risk factors are known, but the majority of the genetic background is still unknown. Linkage disequilibrium-based association is a powerful tool for mapping disease genes and is suitable for mapping complex traits in founder populations. We report the results of a two-stage, autosome-wide scan for LD with breast cancer. Our aim was to identify genetic risk factors for sporadic breast cancer in an eastern Finnish population. Our case-control set is from the province of northern Savo in the late-settlement area of eastern Finland. This population is relatively young and genetically homogeneous. We used 435 autosomal microsatellite markers spaced by an average of 10 cM in a set of 49 breast cancer cases and 50 controls. In the first-stage scan, we found 21 markers in LD with breast cancer (Ps = 0.003-0.046, Fisher's exact test). In the second-stage scan with markers flanking 21 positive loci, four significant markers were found (Ps = 0.013-0.046, Fisher's exact test). Haplotype analysis using global score method with two, three, or four markers also revealed four positive marker combinations (simulated P for global score = 0.003-0.021). Our results suggest breast cancer-associated regions on 3p26, 11q23, and 22q13.1 in an eastern Finnish population.

Adult↗