Population aging increases the need for knowledge on positive aspects of aging, and contributions of older people to their own wellbeing and that of others. We defined active aging as an individual's striving for elements of wellbeing with activities as per their goals, abilities and opportunities. This study examines associations of health, health behaviors, health literacy and functional abilities, environmental and social support with active aging and wellbeing. We will develop and validate assessment methods for physical activity and physical resilience suitable for research on older people, and examine their associations with active aging and wellbeing. We will examine cohort effects on functional phenotypes underlying active aging and disability.
For this population-based study, we plan to recruit 1000 participants aged 75, 80 or 85 years living in central Finland, by drawing personal details from the population register. Participants are interviewed on active aging, wellbeing, disability, environmental and social support, mobility, health behavior and health literacy. Physical activity and heart rate are monitored for 7 days with wearable sensors. Functional tests include hearing, vision, muscle strength, reaction time, exercise tolerance, mobility, and cognitive performance. Clinical examination by a nurse and physician includes an electrocardiogram, tests of blood pressure, orthostatic regulation, arterial stiffness, and lung function, as well as a review of chronic and acute conditions and prescribed medications. C-reactive protein, small blood count, cholesterol and vitamin D are analyzed from blood samples. Associations of factors potentially underlying active aging and wellbeing will be studied using multivariate methods. Cohort effects will be studied by comparing test results of physical and cognitive functioning with results of a cohort examined in 1989-90.
The current study will renew research on positive gerontology through the novel approach to active aging and by suggesting new biomarkers of resilience and active aging. Therefore, high interdisciplinary impact is expected. This cross-sectional study will not provide knowledge on temporal order of events or causality, but an innovative cross-sectional dataset provides opportunities for emergence of novel creative hypotheses and theories.
Exercise behavior, cardiorespiratory fitness, and obesity are strongly influenced by genetic factors. By studying young adult twins, we examined to what extent these interrelated traits have shared genetic and environmental etiologies. We studied 304 twin individuals selected from the population-based FinnTwin16 study. Physical activity was assessed with the Baecke questionnaire, yielding three indexes: sport index, leisure-time index, and work index. In this study, we focused on sport index, which describes sports participation. Body composition was determined using dual-energy X-ray absorptiometry and cardiorespiratory fitness using a bicycle ergometer exercise test with gas exchange analysis. The Baecke sport index was associated with high maximal oxygen uptake adjusted for lean body mass (Vo(2max)[adj]) (r = 0.40), with low body fat percentage (BF%) (r = -0.44) and low waist circumference (WC) (r = -0.29). Heritability estimates for the key traits were as follows: 56% for sport index, 71% for Vo(2max)[adj], 77% for body mass index, 66% for WC, and 68% for BF%. The association between sport index and Vo(2max) was mostly explained by genetic factors (70%), as were both the association between sport index and BF% (71%) and that between sport index and WC (59%). Our results suggest that genetic factors explain a considerable part of the associations between sports participation, cardiorespiratory fitness, and obesity.
To profile participants based on reported outdoor physical activity barriers using a data-driven approach, describe the profiles and study their association with unmet physical activity need.
Cross-sectional analyses of 848 community-dwelling men and women aged 75-90 living in Central Finland in 2012. Barriers to outdoor physical activity and unmet physical activity need were enquired with a questionnaire. The latent profiles were identified by profiling participants into latent groups using a mixture modeling technique on the multivariate set of indicators of outdoor physical activity barriers. A path model was used to study the associations of the profiles with unmet physical activity need.
Five barrier profiles were identified. Profile A was characterized with minor barriers, profile B with weather barriers, profile C with health and weather barriers, profile D with barriers concerning insecurity, health and weather; and profile E with mobility and health barriers. The participants in the profiles differed in the proportion of individual and environmental barriers. The risk for unmet physical activity need was highest among people whose severe mobility difficulties restricted their outdoor physical activity.
Outdoor physical activity barriers reflect the imbalance in person-environment fit among older people, manifested as unmet physical activity need.
In older adults, mobility limitations often coexist with overweight or obesity, suggesting that similar factors may underlie both traits. This study examined the extent to which genetic and environmental influences explain the association between adiposity and mobility in older women. Body fat percentage (bioimpedance test), walking speed over 10 m, and distance walked in a 6-min test were evaluated in 92 monozygotic (MZ) and 104 dizygotic (DZ) pairs of twin sisters reared together, aged 63-76 years. Genetic and environmental influences on each trait were estimated using age-adjusted multivariate genetic modeling. The analyses showed that the means (and s.d.) for body fat percentage, walking speed, and walking endurance were 33.2+/-7.3%, 1.7+/-0.3 m/s and 529.7+/-75.4 m, respectively. The phenotypic correlation between adiposity and walking speed was -0.32 and between adiposity and endurance it was -0.33. Genetic influences explained 80% of the association between adiposity and speed, and 65% of adiposity and walking endurance. Cross-trait genetic influences accounted for 12% of the variability in adiposity, 56% in walking speed, and 34% in endurance. Trait-specific genetic influences were also detected for adiposity (54%) and walking endurance (13%), but not speed. In conclusion, among community-living older women, an inverse association was found between adiposity and mobility that was mostly due to the effect of shared genes. This result suggests that the identification of genetic variants for body fat metabolism may also provide understanding of the development of mobility limitations in older women.
We estimated genetic and environmental variance of BMI among 7245 non-pregnant MZ and DZ pairs of the same sex from the population-based Finnish Twin Cohort. The contributions of additive genetic effects, shared and non-shared environmental effects on age-adjusted BMI-variance were estimated by LISREL structural equation models. Genetic effects contribute 72% in men and 66.4% in non-pregnant women of total variance, while 27.8% of variance among men and 33.6% among women is due to non-shared environmental effects. Shared environmental effects were nonsignificant (0% for women and 0.2% for men). Similar values were obtained for hereditary and non-shared environmental effects, when shared environmental effects were not included in the model. The inclusion of pregnant women did not substantially change heritability estimates.
Eighteen pairs of monozygotic twins discordant for long-term occupational exposure to organic solvents were examined for disturbances of cardiovascular reflexes. All of the subjects were asymptomatic, and considered themselves healthy. No significant differences were observed between the exposed and the nonexposed twins. The finding suggests that occupational solvent exposure at these particular levels is unlikely to cause disturbances of the autonomic nervous function.
Genetic influences on variability of body weight and onset of menarche are well known. To investigate the genetic and environmental contributions to the association of body weight with onset of menarche, we studied Finnish twins from consecutive birth cohorts (the FinnTwin16 study) ascertained from the national population registry, which identifies nearly 100% of all living twins. Baseline questionnaires were mailed to the twins within 60 days of their sixteenth birthday and later to older sibs of the twins. Pairwise response rates (approximately 85% across gender and zygosity) and 30 months of data collection yielded results from 1283 twin pairs. The questionnaires included a survey of health habits and attitudes, a symptom checklist, MMPI personality scales, and a survey of relationships with parents, peers, and the co-twin. Age at menarche was reported by 468 monozygotic (MZ) girls, 378 girls from like-sex dizygotic (FDZ) pairs, 434 girls from opposite-sex (OSDZ) pairs, and 141 older female sibs of the twins. The one-month test-retest reliability of age at menarche in an independent sample (N = 136) of 16-year-olds from a national survey was 0.96. Girls from OSDZ pairs had a significantly higher mean age at menarche (13.33 yr) than FDZ girls (13.13 yr) (difference, 0.20 yr; 95% confidence interval, 0.05-0.35). The MZ correlation for age at menarche was 0.75, the DZ correlation was 0.31, and the sib-twin correlation was 0.32. A bivariate twin analysis of age at menarche and body mass index (wt/ht2) indicated that 37% of the variance in age at menarche can be attributed to additive genetic effects, 37% to dominance effects, and 26% to unique environmental effects. The correlation between additive genetic effects on age at menarche and body mass index was 0.57, indicating a substantial proportion of genetic effects in common.
We studied the cumulative incidence, concordance rate and heritability for diabetes mellitus in a nationwide cohort of 13,888 Finnish twin pairs of the same sex. The twins were born before 1958 and both co-twins were alive in 1967. Data on diabetes were derived through computerized record linkage from death certificates, the National Hospital Discharge Register and the National Drug Register. Records were reviewed in order to assign a diagnostic category to the 738 diabetic patients identified. Of these patients 109 had Type 1 (insulin-dependent) diabetes, 505 Type 2 (non-insulin-dependent) diabetes, 46 gestational diabetes, 24 secondary diabetes, 38 impaired glucose tolerance and 16 remained unclassified. The cumulative incidence of diabetes was 1.4% in men and 1.3% in women aged 28-59 years and 9.3% and 7.0% in men and women aged 60 years and over, respectively. The cumulative incidence did not differ between monozygotic and dizygotic twins. The concordance rate for Type 1 diabetes was higher among monozygotic (23% probandwise and 13% pairwise) than dizygotic twins (5% probandwise and 3% pairwise). The probandwise and pairwise concordance rates for Type 2 diabetes were 34% and 20% among monozygotic twins and 16% and 9% in dizygotic twins, respectively. Heritability for Type 1 diabetes was greater than that for Type 2 where both genetic and environmental effects seemed to play a significant role.
In 1975 and again in 1981, all adult twins in the population-based Finnish Twin Cohort were administered postal questionnaires yielding data on self-reported frequency and quantity of alcohol use. The longitudinal results provide information on the age-to-age stability of social drinking patterns among 13,404 (twin) individuals aged 18 to 43 at baseline; model-fitting the cross-temporal consistency of the twins' reported alcohol use yields unique estimates of the contribution of genetic and environmental factors to their individual age-to-age stabilities. Mean consumption levels did not change between 1975 and 1981. Patterns of social drinking were more stable in older (aged 24-43 at baseline) than younger (aged 18-23 at baseline) adult twins, and were more stable among men than women. Heritabilities were significant at both baseline and follow-up for all three alcohol measures in both genders and both age groups, with a median magnitude of 0.48. Both longitudinal genetic and environmental covariances were significant, and both were generally higher among older pairs. Genetic covariances (median magnitude = 0.68) were significantly higher than environmental covariances (median = 0.36). Analyses of absolute changes in alcohol use revealed heritable influences on the disposition to change. We conclude that genes contribute to both consistency and change in patterns of alcohol use from early to midadulthood.
To study twin resemblance for weight change (delta wt) and to assess the consistency of body mass index (BMI) over 6 years.
6 year follow-up based on identical mailed questionnaires in 1975 (baseline) and in 1981 (follow-up).
5967 same-sexed non-pregnant Finnish twin pairs aged 18-54 in 1975 (1106 male and 862 female monozygotic (MZ) and 2430 male and 1569 female dizygotic (DZ) pairs).
Intra-pair correlations of delta wt and BMI, estimates of genetic and environmental components of variance of delta wt and BMI.
Unadjusted mean delta wt was +2.0 (s.d. = 4.6) kg among MZ and 2.1 (4.9) kg among DZ male individuals. Corresponding values among MZ and DZ female individuals were +1.5 (4.4) kg and +1.7 (4.4) kg, respectively. Age and initial BMI together explained 8.0% of the male and 2.3% of the female phenotypic variance of delta wt. The intraclass correlations for delta wt (adjusted for age and initial BMI) for all pairs were 0.29 and 0.07 for MZ and DZ men and 0.25 and 0.05 for MZ and DZ women, respectively. The BMI of the twins increased slightly during the follow-up compared to the baseline values (23.9 (2.7) for MZ and 24.1 for DZ men and 23.0 (3.3) for MZ and 23.2 (3.42) for DZ women). The intra-class correlations for BMI at baseline (0.69 for MZ and 0.34 for DZ men and 0.67 for MZ and 0.29 for DZ women) were almost identical with the correlations at follow-up (0.67 for MZ and 0.32 for DZ men and 0.69 for MZ and 0.29 for DZ women). The intra-class correlations for both BMI and delta wt were consistently higher among pairs living together than among pairs living apart at baseline and at follow-up in both zygosity groups (MZ and DZ). Among pairs living apart at baseline, the longitudinal model for BMI showed that the correlation between genetic effects at baseline and at follow-up was very high (> 0.9 in all age groups among both genders). The correlations for environmental effects ranged from 0.50 to 0.67 during the follow-up period.
Weight changes in adults over a 6-year period appear to be determined by environmental effects rather than genetic factors. However, the genetic component in BMI is considerable and stable over time. Shared environment is likely to contribute to the resemblance of both delta wt and BMI among adult twin pairs, especially among MZ pairs.
The aim of this study was to analyze whether the associations between perceived environmental and individual characteristics and perceived walking limitations in older people differ between those with intact and those with poorer lower extremity performance.
Persons aged 75 to 90 ( N = 834) participated in interviews and performance tests in their homes. Standard questionnaires were used to obtain walking difficulties; environmental barriers to and, facilitators of, mobility; and perceived individual hindrances to outdoor mobility. Lower extremity performance was tested using Short Physical Performance Battery (SPPB).
Among those with poorer lower extremity performance, the likelihood for advanced walking limitations was, in particular, related to perceived poor safety in the environment, and among those with intact performance to perceived social issues, such as lack of company, as well as to long distances.
The environmental correlates of walking limitations seem to depend on the level of lower extremity performance.
Environmental barriers are associated with disability-related outcomes in older people but little is known of the effect of environmental barriers on mortality. The aim of this study was to examine whether objectively measured barriers in the outdoor, entrance and indoor environments are associated with mortality among community-dwelling 80- to 89-year-old single-living people.
This longitudinal study is based on a sample of 397 people who were single-living in ordinary housing in Sweden. Participants were interviewed during 2002-2003, and 393 were followed up for mortality until May 15, 2012.Environmental barriers and functional limitations were assessed with the Housing Enabler instrument, which is intended for objective assessments of Person-Environment (P-E) fit problems in housing and the immediate outdoor environment. Mortality data were gathered from the public national register. Cox regression models were used for the analyses.
A total of 264 (67%) participants died during follow-up. Functional limitations increased mortality risk. Among the specific environmental barriers that generate the most P-E fit problems, lack of handrails in stairs at entrances was associated with the highest mortality risk (adjusted RR 1.55, 95% CI 1.14-2.10), whereas the total number of environmental barriers at entrances and outdoors was not associated with mortality. A higher number of environmental barriers indoors showed a slight protective effect against mortality even after adjustment for functional limitations (RR 0.98, 95% CI 0.96-1.00).
Specific environmental problems may increase mortality risk among very-old single-living people. However, the association may be confounded by individuals' health status which is difficult to fully control for. Further studies are called for.
We investigated whether BMI predicts type 2 diabetes in twins and to what extent that is explained by common genetic factors.
This was a population-based twin cohort study. Monozygotic (n = 4,076) and dizygotic (n = 9,109) non-diabetic twin pairs born before 1958 answered a questionnaire in 1975, from which BMI was obtained. Information on incident cases of diabetes was obtained by linkage to nationwide registers until 2005.
Altogether, 1,332 twins (6.3% of men, 5.1% of women) developed type 2 diabetes. The HR for type 2 diabetes increased monotonically with a mean of 1.22 (95% CI 1.20-1.24) per BMI unit and of 1.97 (95% CI 1.87-2.08) per SD of BMI. The HRs for lean, overweight, obese and morbidly obese participants were 0.59, 2.96, 6.80 and 13.64 as compared with normal weight participants. Model heritability estimates for bivariate variance due to an additive genetic component and non-shared environmental component were 75% (men) and 71% (women) for BMI, and 73% and 64%, respectively for type 2 diabetes. The correlations between genetic variance components (r (g)) indicated that one fifth of the covariance of BMI and type 2 diabetes was due to shared genetic influences. Although the mean monozygotic concordance for type 2 diabetes was approximately twice the dizygotic one, age of onset of diabetes within twin pair members varied greatly, irrespective of zygosity.
A 28-year follow-up of adult Finnish twins showed that despite high trait heritability estimates, only a fraction of covariation in BMI and incident type 2 diabetes was of genetic origin.
This study identifies, in genetically informative data, familial and socioregional environmental influences on abstinence from alcohol at age 16.
Data are from FinnTwin 16, a population-based study of five consecutive birth cohorts of Finnish twins (N = 5,747 twin individuals), yielding 2,711 pairs of known zygosity. Measures of alcohol use, embedded into a health-habits questionnaire, were taken from earlier epidemiological research with nontwin Finnish adolescents. The questionnaire was administered sequentially to all twins as they reached age 16. Separate questionnaires, including measures of alcohol use and screening questions for alcohol problems, were received from 5,243 of the twins' parents.
Abstinence from alcohol to age 16 exhibits very significant familial aggregation, largely due to nongenetic influences. Abstinence rates are influenced by socioregional variation, sibling interaction effects and parental drinking patterns. Sibling and parental influences are greater in some regional environments than in others: the relative likelihood that a twin abstains, given that the co-twin does, or that both parents do, is shown to be modulated by socioregional variation.
Environmental contexts affect the likelihood of maintaining abstinence from alcohol to midadolescence, and socioregional variation modulates influences of siblings and parents. The results illustrate how genetically informative data can inform prevention research by identifying target variables for intervention efforts.
To study which individual characteristics and environmental factors correlate with fear of moving outdoors and whether fear of moving outdoors predicts development of mobility limitation.
Observational prospective cohort study and cross-sectional analyses.
Community and research center.
Seven hundred twenty-seven community-living people aged 75 to 81 were interviewed at baseline, of whom 314 took part in a 3.5-year follow-up.
Fear of moving outdoors and its potential individual and environmental correlates were assessed at baseline. Perceived difficulties in walking 0.5 km and 2 km were assessed twice a year over a 3.5-year period.
At baseline, 65% of the women and 29% of the men reported fear of moving outdoors. Poor socioeconomic status; musculoskeletal diseases; slow walking speed; and the presence of poor street conditions, hills in the nearby environment, and noisy traffic correlated with fear of moving outdoors. At the first 6-month follow-up, participants with fear of moving outdoors had more than four times the adjusted risk (odds ratio (OR)=4.6, 95% confidence interval (CI)=1.92-11.00) of developing difficulties in walking 0.5 km and a three times greater adjusted risk (OR=3.10, 95% CI=1.49-6.46) for developing difficulty in walking 2 km compared with those without fear. The difference in the prevalence of walking difficulties remained statistically significant over the 3.5-year follow-up (P=.02 and P=.009, respectively).
Fear of moving outdoors is common in older adults and increases the risk of developing self-reported difficulties in walking 0.5 km and 2 km. Knowledge about individual and environmental factors underlying fear of moving outdoors and finding ways to alleviate fear of moving outdoors are important for community planning and prevention of disability.
The nature of the association between body height and educational attainment found in previous studies remains to be clarified. The aim of this study was to examine factors contributing to this association by using a large Finnish twin data set (8798 adult twin pairs) gathered by questionnaire in 1981. A bivariate twin analysis was used to determine whether the genetic and environmental factors behind body height and educational attainment correlate with each other. A high heritability was found for body height (h2 = 0.78 in men and h2 = 0.75 in women), and a moderate heritability for education (h2 = 0.47 and h2 = 0.43, respectively). Shared environmental effects were also important in body height (c2 = 0.12 in men and c2 = 0.11 in women) and education (c2 = 0.36 and c2 = 0.43, respectively). A high correlation (r(c) = 0.77 in men, r(c) = 0.58 in women) of shared environmental factors education and body height, and weaker correlations (r = 0.11 and r = 0.08, respectively) of unshared environmental factors were found. The correlation of genetic factors between these two characteristics was not statistically significant. The results suggest that the association between body height and education is due mainly to nongenetic family factors.
To study genetic and environmental factors affecting body mass index (BMI) and BMI phenotypic correlations across adolescence.
Prospective, population-based, twin cohort study.
We used twin modeling in 2413 monozygotic and same-sex and opposite-sex dizygotic Finnish twin pairs born in 1983-1987 and assessed using self-report questionnaires at 11-12, 14 and 17 years of age.
Heritability of BMI was estimated to be 0.58-0.69 among 11-12- and 14-year-old boys and girls, 0.83 among 17-year-old boys and 0.74 among 17-year-old girls. Common environmental effects shared by siblings were 0.15-0.24 among 11-12- and 14-year-old boys and girls but no longer discernible at 17 years of age. Unique environmental effects were 0.15-0.23. Additive genetic factors explained 90-96% of the BMI phenotypic correlations across adolescence, whereas unique environmental factors explained the rest. Common environment had no effect on BMI phenotypic correlations.
The genetic contribution to BMI is strong during adolescence, and it mainly explains BMI phenotypic correlations across adolescence. Common environmental factors have an effect on BMI during early adolescence, but that effect disappears by late adolescence.
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The aim of the present study was to examine the contribution of genetic and environmental factors to depressive symptoms among older women. The participants were 102 monozygotic and 115 dizygotic female twin pairs aged 64 to 76 years. Depressive symptoms were assessed by the Center for the Epidemiologic Studies Depression Scale. The contribution of genetic and environmental effects was estimated for the constructed depressiveness factor and for the subscales which were depressed mood, psychomotor retardation, lack of wellbeing and interpersonal difficulties. Of the variance in depressiveness, shared environmental influences accounted for 39% and nonshared environmental influences 61%. For the subscales, 24% to 62% of the variance was explained by individual, and 13% to 23% by shared, environmental factors. Lack of wellbeing had its own moderate additive genetic effect explaining 30% of the variance. This study showed that in older women predominantly environmental factors underlay individual differences in depressiveness; however, the factors varied to some extent between dimensions measured by the subscales.
The purpose of the present study was to examine the relative contribution of genetic and environmental effects on the air-conducted hearing threshold levels at low (0.125-0.5 kHz), mid (1-2 kHz), and high (4-8 kHz) frequencies separately for the better and worse hearing ear in older women. We also examined the distribution of audiogram configurations. Data was analysed using quantitative genetic modelling. As part of the Finnish twin study on aging (FITSA), hearing was measured in 103 monozygotic and 114 dizygotic female twin pairs aged 63-76 years. Approximately every third subject had a flat type, and two-thirds a descending type of audiogram configuration. No significant difference was observed in the distribution of audiogram configurations between zygosity groups. In the better ear, additive genetic effects accounted for 64%-74% of the total variance at different frequencies. For the worse ear, environmental effects were larger. Although overall heritability is rather constant across the frequency spectrum, it is noteworthy that at low and high frequencies frequency-specific genetic and environmental effects together accounted for the majority of the total variance.