Healthy Finnish Adults Research Articles

Low rate of asymptomatic carriage and salivary immunoglobulin A response to Group A Streptococci in the healthy adult population in Finland

Streptococcus pyogenes, also called group A streptococcus (GAS), is a human pathogen causing a wide range of infections ranging from mild tonsillitis to severe, life threatening conditions such as bacteraemia, necrotizing fasciitis, and streptococcal toxic shock syndrome. GAS may also colonise the oropharynx without causing any signs of disease which is known as asymptomatic carriage. This study aims to investigate IgA responses against GAS and oral streptococci from saliva samples collected from healthy Finnish adults. In addition, asymptomatic throat GAS carriage was studied. The study participants consisted of healthy adult volunteers who provided one saliva sample, a throat swab, and a background questionnaire. Total salivary IgA, and GAS specific IgA were analysed from the saliva samples using enzyme-linked immunosorbent assays (ELISA) and the results were compared to oral streptococci specific IgA levels. Asymptomatic GAS throat carriers were identified by bacterial culture, and the isolates were emm typed. Samples from a total of 182 individuals were analysed. The median salivary IgA concentration was 62.9 µg/ml (range 17.3–649.9 µg/ml), and median GAS and oral streptococcal specific IgA concentrations 2.7 and 3.3 arbitrary units (AU, range 1.4–7.4 AU and 1.6–12.0 AU), respectively. Three individuals with asymptomatic GAS throat carriage were identified.

Genetic Risk Score for Serum 25-Hydroxyvitamin D Concentration Helps to Guide Personalized Vitamin D Supplementation in Healthy Finnish Adults

Genetic factors modify serum 25-hydroxyvitamin D [25(OH)D] concentration and can affect the optimal intake of vitamin D. We aimed to personalize vitamin D supplementation by applying knowledge of genetic factors affecting serum 25(OH)D concentration. We performed a genome-wide association study of serum 25(OH)D concentration in the Finnish Health 2011 cohort (n=3339) using linear regression and applied the results to develop a population-matched genetic risk score (GRS) for serum 25(OH)D. This GRS was used to tailor vitamin D supplementation for 96 participants of a longitudinal Digital Health Revolution (DHR) Study. The GRS, serum 25(OH)D concentrations, and personalized supplementation and dietary advice were electronically returned to participants. Serum 25(OH)D concentrations were assessed using immunoassays and vitamin D intake using FFQs. In data analyses, cross-sectional and repeated-measures statistical tests and models were applied as described in detail elsewhere. GC vitamin D-binding protein and cytochrome P450 family 2 subfamily R polypeptide 1 genes showed genome-wide significant associations with serum 25(OH)D concentration. One single nucleotide polymorphism from each locus (rs4588 and rs10741657) was used to develop the GRS. After returning data to the DHR Study participants, daily vitamin D supplement users increased from 32.6% to 60.2% (P=6.5× 10-6) and serum 25(OH)D concentration from 64.4 ± 20.9 nmol/L to 68.5 ± 19.2 nmol/L (P=0.006) between August and November. Notably, the difference in serum 25(OH)D concentrations between participants with no risk alleles and those with 3 or 4 risk alleles decreased from 20.7nmol/L to 8.0nmol/L (P=0.0063). We developed and applied a population-matched GRS to identify individuals genetically predisposed to low serum 25(OH)D concentration. We show how the electronic return of individual genetic risk, serum 25(OH)D concentrations, and factors affecting vitamin D status can be used to tailor vitamin D supplementation. This model could be applied to other populations and countries.

Replacing Animal-Based Proteins with Plant-Based Proteins Changes the Composition of a Whole Nordic Diet-A Randomised Clinical Trial in Healthy Finnish Adults.

Increased consumption of plant-based foods and decreased consumption of animal-based foods is recommended for healthy diets and sustainable food production. We investigated the effects of partial replacement of dietary animal proteins with plant-based ones on intake of energy-yielding nutrients, fibre, and plasma lipoproteins. This 12-week randomised clinical intervention comprised 107 women and 29 men (20–69 years) in three diet groups with different dietary protein compositions (“ANIMAL”: Animal 70%/plant 30%; “50/50”: Animal 50%/plant 50%; “PLANT”: Animal 30%/plant 70%; all: Protein intake 17 E%). Nutrient intakes were assessed by 4-day food records. Saturated fat intake (E%) was lower and polyunsaturated fatty acid intake (E%) higher in the PLANT and 50/50 groups compared to the ANIMAL group (p < 0.001 for all). Fibre intake was higher in the PLANT (p ˂ 0.001) and 50/50 (p = 0.012) groups. Total and LDL cholesterol were lower in the PLANT than in the ANIMAL group (p = 0.003 for both) but no differences in HDL cholesterol or triglycerides were observed (p > 0.05). Replacing animal protein with plant protein sources in the diet led to an increased fibre intake and improved dietary fat quality as well as blood lipoprotein profile. Flexitarian diets could provide healthy and more sustainable alternatives for the current, predominantly animal-based diets.

Training of Verbal Working Memory at Sentence Level Fails to Show Transfer

During the past decades, working memory (WM) training has attracted considerable research attention, but its transfer to untrained tasks is still controversial. In a randomized controlled trial, we investigated the possible transfer effects of a novel sentence-level WM training regime. Sixty-eight healthy Finnish adults were randomized into either a WM training group or an active control group. The WM training group practiced for four weeks with two adaptive sentence-level WM training tasks, namely a novel sentence-level updating task and a reading span task. The active control group practiced on a quiz task that called for long-term memory but did not load on WM. There were no statistically significant training effects on the pre-post measures of near and far transfer. We suggest that the lack of training effects may reflect the specificity and automaticity of the sentence processing system.

Music and speech prosody: a common rhythm

Disorders of music and speech perception, known as amusia and aphasia, have traditionally been regarded as dissociated deficits based on studies of brain damaged patients. This has been taken as evidence that music and speech are perceived by largely separate and independent networks in the brain. However, recent studies of congenital amusia have broadened this view by showing that the deficit is associated with problems in perceiving speech prosody, especially intonation and emotional prosody. In the present study the association between the perception of music and speech prosody was investigated with healthy Finnish adults (n = 61) using an on-line music perception test including the Scale subtest of Montreal Battery of Evaluation of Amusia (MBEA) and Off-Beat and Out-of-key tasks as well as a prosodic verbal task that measures the perception of word stress. Regression analyses showed that there was a clear association between prosody perception and music perception, especially in the domain of rhythm perception. This association was evident after controlling for music education, age, pitch perception, visuospatial perception, and working memory. Pitch perception was significantly associated with music perception but not with prosody perception. The association between music perception and visuospatial perception (measured using analogous tasks) was less clear. Overall, the pattern of results indicates that there is a robust link between music and speech perception and that this link can be mediated by rhythmic cues (time and stress).

The interaction between serotonin receptor 2A and catechol-O-methyltransferase gene polymorphisms is associated with the novelty-seeking subscale impulsiveness

Novelty seeking is a trait that has been consistently associated with problem behaviours. There is evidence for heritability of novelty seeking, but the molecular genetic basis of the trait is still widely unclear. The interaction between polymorphisms of catechol-O-methyltransferase (COMT) and serotonin receptor 2A genes was examined in relation to novelty seeking and its different subscales in healthy Finnish adults. A subsample of 1214 participants derived from a population-based sample was genotyped for the COMT Val158Met (rs4680) and HTR2A T102C (rs6313) genes. Novelty seeking was measured twice, with a 4-year interval, using Cloninger's Temperament and Character Inventory. The interaction between COMT Val158Met and HTR2A T102C polymorphisms was found to be associated with subscale impulsiveness. T/T carriers of HTR2A T102C polymorphism, that also had Met/Met genotype of COMT Val158Met single nucleotide polymorphism, scored significantly higher on impulsiveness than Val allele carriers (P=0.005). Our results suggest that the interaction between dopaminergic and serotonergic genes might underlie impulsiveness. Together with earlier research our results also stress the importance of considering novelty seeking as a heterogeneous trait with its subscales having different genetic backgrounds.

Cardiovascular risk scores in the prediction of subclinical atherosclerosis in young adults: evidence from the cardiovascular risk in a young Finns study

To study the utility of risk scores in the prediction of subclinical atherosclerosis in young adults. Participants were 2204 healthy Finnish adults aged 24-39 years in 2001 from a population-based follow-up study Cardiovascular Risk in Young Finns. We examined the performance of the Framingham, Reynolds, Systematic Coronary Risk Evaluation (SCORE), PROCAM, and Finrisk cardiovascular risk scores to predict subclinical atherosclerosis, that is carotid artery intima-media thickness (IMT) and plaque, carotid artery distensibility (CDist), and brachial artery flow-mediated dilatation (FMD) 6 years later. In a 6-year prediction of high IMT (highest decile or plaque), areas under the receiver operating characteristic curves (AUC) for baseline Finrisk (0.733), SCORE (0.726), PROCAM (0.712), and Reynolds (0.729) risk scores were similar as for Framingham risk score (0.728, P always ≥0.15). All risk scores had a similar discrimination in predicting low CDist (lowest decile) (0.652, 0.642, 0.639, 0.658, 0.652 respectively, P always ≥0.41). In the prediction of low FMD (lowest decile), Finrisk, PROCAM, Reynolds, and Framingham scores had similar AUCs (0.578, 0.594, 0.582, 0.568, P always ≥0.08) and SCORE discriminated slightly better (AUC=0.596, P<0.05). The prediction of subclinical outcomes was consistent when estimated from other statistical measures of discrimination, reclassification, and calibration. Cardiovascular disease risk scores had equal value in predicting subclinical atherosclerosis measured by IMT and CDist in young adults. SCORE was more accurate in predicting low FMD than Framingham risk score.

Tracking of Noninvasive Ultrasound Measurements of Subclinical Atherosclerosis in Adulthood: Findings from the Cardiovascular Risk in Young Finns Study

We examined tracking of ultrasound measurements of vascular structure and function in adulthood using data collected in the 2001 and 2007 follow-ups of Cardiovascular Risk in Young Finns Study. B-mode ultrasound measures of carotid artery intima-media thickness (IMT), carotid artery distensibility (CDist) and brachial artery flow-mediated dilatation (FMD) was obtained on 1809 apparently healthy Finnish adults aged 24 to 39 years in 2001 (1014 females; 795 males). Significant 6-year tracking was observed for IMT (males, r = 0.56; females, r = 0.46), CDist (males, r = 0.35; females, r = 0.36) and FMD (males, r = 0.23; females, r = 0.20). Subjects with 10-year risk of CVD (according to the SCORE risk score) above sex-specific median had improved IMT (r = 0.44; r = 0.57, p = 0.0001) and CDist (r = 0.31; r = 0.40, p = 0.03) tracking compared with those below median. Body mass index (BMI) ≥ 30 kg/m 2 decreased tracking of CDist (r = 0.36; r = 0.19, p = 0.01). In conclusion, ultrasound measurements tracked low to moderate over 6-years and was influenced by cardiovascular disease (CVD) risk factor status. (E-mail: juho.raiko@utu.fi)

Follow‐ups of the Cardiovascular Risk in Young Finns Study in 2001 and 2007: Levels and 6‐year changes in risk factors

To examine cardiovascular risk factor levels in 2007 and their 6-year changes between 2001 and 2007 using the data collected in the follow-ups of the Cardiovascular Risk in Young Finns Study. Population-based follow-up study. A total of 2204 healthy Finnish adults aged 30-45 years (1210 women; 994 men). Levels in 2007 and changes between 2001 and 2007 of lipids, insulin, glucose, blood pressure, smoking, body mass index, alcohol consumption, waist and hip circumferences. The mean serum total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol and triglyceride concentrations in 30- to 45-year-old adults were 5.05, 3.09, 1.34 and 1.40 mmol L(-1), respectively. Significant changes (P < 0.05) between 2001 and 2007 in 30- to 39-year-old subjects included a decrease in total cholesterol (-6.6% in men, -5.8% in women), LDL-cholesterol (-10.2% and -11.6%) and an increase in diastolic blood pressure (3.5% and 3.9%). Waist circumference (1.8% and 5.5%) and systolic blood pressure increased in 36-39 year olds (2.3% and 2.3%). HDL-cholesterol increased in 30- to 33-year-old women (5.8%) Glucose levels increased in 30- to 39-year-old women (3.7%) and 36- to 39-year-old men (3.6%). Smoking prevalence decreased in 36- to 39-year-old men from 29.8% to 22.2%. The 6-year changes in total cholesterol, LDL-cholesterol and HDL-cholesterol in young Finns were favourable between 2001 and 2007. However, waist circumference, glucose and blood pressure levels increased. Therefore, continuous efforts are still needed in fighting against cardiovascular risk factors.

Life satisfaction and depression in a 15-year follow-up of healthy adults

The aim of this study was to investigate the cross-sectional and longitudinal relationship between life satisfaction and depressive symptoms in healthy adults. This is a 15-year prospective cohort study with a nationwide sample of healthy Finnish adults (N = 9679), aged 18-45, who responded to postal questionnaires in 1975, 1981 and 1990 including a 4-item life satisfaction (LS) scale (range 4-20) and, in 1990, the 21-item Beck Depression Inventory (BDI). A strong linear association was found between concurrent LS and BDI scales (r = 0.6). With an LS cut-off point of 11/12, moderate/severe depression (BDI > or = 19) was detected with 87% sensitivity, 88 % specificity and a 94% area under the ROC curve. Longitudinally, a strongly increased risk of moderate/severe depression in 1990 was observed among the dissatisfied (LS 12-20) compared with the satisfied (LS 4-6) in 1975 (OR = 6.7; 95 %CI 4.2-10.9) and in 1981 (OR = 10.4; 6.1-17.6). The 4-item LS scale can identify a group of healthy people from the general population with a high risk of having or developing depressive symptoms. Since low life satisfaction also indicates an elevated risk of other adverse health outcomes, the assessment of subjective well-being should be encouraged both in surveys and in clinical practice.

Genetic heterogeneity and functional properties of intestinal bifidobacteria.

The aim of the present study was to compare several molecular methods for the identification and genotyping of bifidobacteria, and further to investigate genetic heterogeneity and functional properties of bifidobacterial isolates from intestinal samples of Finnish adult subjects. A total of 153 intestinal bifidobacterial isolates were included in initial screening and 34 isolates were further characterized. Identification results obtained with PCR-ELISA and ribotyping were well in accordance with each other, while randomly amplified polymorphic DNA (RAPD) gave tentative identification only to Bifidobacterium bifidum and to 65% of the B. longum isolates. The most commonly detected species were B. longum biotype longum followed by B. adolescentis and B. bifidum. In addition, B. animalis (lactis), B. angulatum and B. pseudocatenulatum were found. Ribotyping and pulsed-field gel electrophoresis (PFGE) proved to be discriminatory methods for bifidobacteria, but also RAPD revealed intraspecies heterogeneity. Besides two B. animalis (lactis) isolates with very close similarity to a commercially available probiotic strain, none of the intestinal isolates showed optimal survival in all tolerance (acid, bile and oxygen) or growth performance tests. Several species/strains of bifidobacteria simultaneously colonize the gastrointestinal tract of healthy Finnish adults and intestinal Bifidobacterium isolates were genetically heterogeneous. Functional properties of bifidobacteria were strain-dependent. Applicability of ribotyping with the automated RiboPrinter System for identification and genotyping of bifidobacteria was shown in the present study.

Self-reported life satisfaction and 20-year mortality in healthy Finnish adults.

The authors investigated the role of self-reported life satisfaction in mortality with a prospective cohort study (1976-1995). A nationwide sample of healthy adults (18-64 years, n = 22,461) from the Finnish Twin Cohort responded to a questionnaire about life satisfaction and known predictors of mortality in 1975. A summary score for life satisfaction (LS), defined as interest in life, happiness, loneliness, and general ease of living (scale range, 4-20), was determined and used as a three-category variable: the satisfied (LS, 4-6) (21%), the intermediate group (LS, 7-11) (65%), and the dissatisfied (LS, 12-20) (14%). Mortality data were analyzed with Cox regression. Dissatisfaction was linearly associated with increased mortality. The age-adjusted hazard ratios of all-cause, disease, or injury mortality among dissatisfied versus satisfied men were 2.11 (95% confidence interval (CI): 1.68, 2.64), 1.83 (95% CI: 1.40, 2.39), and 3.01 (95% CI: 1.94, 4.69), respectively. Adjusting for marital status, social class, smoking, alcohol use, and physical activity diminished these risks to 1.49 (95% CI: 1.16, 1.92), 1.35 (95% CI: 1.01, 1.82), and 1.93 (95% CI: 1.19, 3.12), respectively. Dissatisfaction was associated with increased disease mortality, particularly in men with heavy alcohol use (hazard ratio = 3.76, 95% CI: 1.61, 8.80). Women did not show similar associations between life satisfaction and mortality. Life dissatisfaction may predict mortality and serve as a general health risk indicator. This effect seems to be partially mediated through adverse health behavior.

Increased risk of malignant lymphoma indicated by elevated Epstein-Barr virus antibodies--a prospective study.

We estimated Epstein-Barr virus (EBV) antibody-associated relative risks (RR) of malignant lymphoma/leukemia within a cohort of 39,000 healthy Finnish adults followed up for 12 years. Antibody analyses to EBV capsid antigen (VCA), early antigen (EA), and nuclear antigens (EBNA, EBNA1, and EBNA2) were based on concomitantly evaluated ELISA techniques. No increased risk was associated with mere EBV seropositivity. However, elevated EBV EA and EBNA antibody levels were associated with a statistically significant excess risk of malignant lymphoma/leukemia (RREA = 3.4, 95 percent confidence interval [CI] = 1.0-11.0; RREBNA = 4.5, CI = 1.2-16.9). These elevated antibody responses may be due either to destruction of neoplastic EBV positive B-cells and/or to activation of latent EBV infection early in the lymphomagenesis.