Overweight and Obesity in Finnish Children by Parents' Socioeconomic Position-A Registry-Based Study

Objectives: To examine associations between parents' socioeconomic position (SEP) and child overweight and obesity, using registry data. Methods: Data (final n = 194,423) on children's height, weight and parents' SEP were drawn from the national Register of Primary Health Care Visits (Avohilmo) and Statistics Finland. Risk ratios for bernoulli-distributed overweight (RROW) and obesity (RROB) according to SEP were estimated using generalized linear models and using a log -link. Results: The risk for obesity was lower in boys from high-income families (RROB 0.76), for overweight and obesity was lower in boys (RROW 0.72, RROB 0.58) and girls (RROW 0.72, RROB 0.54) with highly educated fathers, in boys (RROW 0.79, RROB 0.58) and girls (RROW 0.78, RROB 0.56) with high-educated mothers and in boys (RROW 0.85, RROB 0.77) and girls (RROW 0.80, RROB 0.69) living in urban areas, as compared to low-income families, low-educated parents, and rural residence, respectively. Conclusion: The risk of overweight and obesity was increased in children with low SEP or rural residence. Administrative registers are a valid approach to monitor childhood obesity by parents' SEP.

Association of socioeconomic position and childhood obesity in Finland: a registry-based study

OBJECTIVE

To identify what dimensions of socioeconomic position (SEP) are most closely associated with childhood obesity in Finland, leveraging population-wide data among the whole child population aged 2-17 years in Finland.

DESIGN

Registry-based study.

SETTING

Data from several administrative registries linked on individual level covering the whole of Finland were used. Data on height and weight measurements in 2018 were obtained from the Register of Primary Health Care visits and data on sociodemographic and socioeconomic indicators (2014-2018) from Statistics Finland.

PARTICIPANTS

Children aged 2-17 years with valid height and weight measurements performed at the child health clinic or school healthcare in 2018 (final n=194 423).

MAIN OUTCOME MEASURES

Obesity was defined according to WHO Growth Reference curves. Sociodemographic and socioeconomic indicators were linked on individual level for adults (both parents) who lived in the same household (42 predictors). Boosted regression model was used to analyse the contribution of SEP to obesity.

RESULTS

From socioeconomic indicators, annual household income (12.6%) and mother and father's educational level (12.6% and 8.1%, respectively) had the highest relative influence on obesity risk. The relative influence of a child's sex was 7.7%.

CONCLUSIONS

The parents' SEP was inversely associated with obesity among the offspring. A remarkable number of objective SEP indicators were analysed with parents' education and household income finally being the indicators most strongly associated with obesity among children. In future research, more attention should be paid to reliable and objective ways of measuring educational status and income rather than on developing new SEP indicators. Administrative registries with information on both healthcare and socioeconomic indicators can in future provide better opportunities to assess the influence of SEP on various health risks.

Occupational complexity and cognition in the FINGER multidomain intervention trial

INTRODUCTION

Lifetime exposure to occupational complexity is linked to late-life cognition, and may affect benefits of preventive interventions.

METHODS

In the 2-year multidomain Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER), we investigated, through post hoc analyses (N = 1026), the association of occupational complexity with cognition. Occupational complexity with data, people, and substantive complexity were classified through the Dictionary of Occupational Titles.

RESULTS

Higher levels of occupational complexity were associated with better baseline cognition. Measures of occupational complexity had no association with intervention effects on cognition, except for occupational complexity with data, which was associated with the degree of intervention-related gains for executive function.

DISCUSSION

In older adults at increased risk for dementia, higher occupational complexity is associated with better cognition. The cognitive benefit of the FINGER intervention did not vary significantly among participants with different levels of occupational complexity. These exploratory findings require further testing in larger studies.

Impact of socioeconomic position on childhood obesity in Finland based on register data from 2018

Background

Obesity is a globally growing public health challenge among children. In developed countries, the risk of obesity is commonly higher among lower socioeconomic groups. Measuring socioeconomic position (SEP), especially income, is challenging in surveys as self-reported information may suffer from reporting, awareness, recall and non-response bias. Our aim is to utilize official register data on several SEP indicators and measured height and weight of children, to identify the strongest predictors of SEP of the parents on the risk of obesity among the whole 2-17-year-old child population in Finland.

Methods

Data for all children who had visited child health clinic or school health care in 2018 were extracted from the National Outpatient Register on Primary Health Care Services (n = 387623, coverage 40% in 2018). Obesity was defined according to the WHO criteria. SEP indicators were obtained from Statistics Finland for both parents living in the same household with a child. Boosted regression model was used to analyze the contribution of SEP to obesity using training dataset on 155479 non-related children.

Results

The area under the curve for the final model in training dataset was 0.736 and 0.718 in validation dataset. Mother's educational level (12.6% of the total explained variation) and household's disposable income (12.6%) were the SEP indicators that most strongly predicted childhood obesity, whereas the impact of educational level of the father was somewhat smaller (8.1%). The influence of the age of a child was even bigger (39.2%), the prevalence of obesity being highest at 11 and 9 years of age among boys and girls, respectively.

Conclusions

Our results based on official register data from Finland, a Nordic high-income country, endorse earlier findings on higher obesity risk among children with low socio-economic family background. Identification of the SEP related risk factors and support to families are essential in the prevention of childhood obesity.

Key messages

Associations of Depressive Symptoms and Cognition in the FINGER Trial: A Secondary Analysis of a Randomised Clinical Trial

Depression and cognition are associated, but the role of depressive symptoms in lifestyle interventions to prevent dementia needs further study. We investigated the intervention effect on depressive symptoms and their associations with cognition in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER; NCT01041989), a two-year multidomain lifestyle trial. One thousand two-hundred and sixty individuals (60-77 years) at risk for dementia were randomised into a multidomain intervention (diet, exercise, cognitive training, and vascular/metabolic risk monitoring) or control group (regular health advice). Depressive symptoms (Zung scale) and cognition (modified Neuropsychological Test Battery) were evaluated at baseline, 12, and 24 months. One thousand one-hundred and twenty-five participants had baseline Zung data. Mean Zung score decreased 0.73 (SD 5.6) points in the intervention and 0.36 (5.6) points in the control group, with nonsignificant between-group difference (group × time coefficient -0.006, 95% CI -0.019 to 0.007). Overall, higher baseline Zung score was associated with less improvement in global cognition (-0.140, p = 0.005) and memory (-0.231, p = 0.005). Participants with clinically significant baseline depressive symptoms (Zung ≥ 40 points) had less intervention benefit to executive functioning (group × time × Zung -0.096, 95% CI -0.163 to -0.028). Change in Zung score was not associated with change in cognition. Clinically significant depressive symptoms warrant more attention when designing dementia-prevention interventions.

Early childhood family background predicts meal frequency behaviour in children: Five-year follow-up study

AIMS

Childhood nutrition patterns have an important role in later health. We studied the role of family type, other family background factors and their changes over a five-year follow-up with respect to meal frequency among children.

METHODS

Longitudinal data were collected in 2007-2009 and 2013-2014. A nationally representative sample of Finnish children (n = 1822) aged 0.5-5 years at baseline and 5-10 years at follow-up and their families were used. The participation rate was 83% at baseline and 54% at follow-up. Meal frequency was defined as four to six meals per day. The associations of meal frequency with family background factors over a five-year follow-up period were examined by bivariate and multivariate regression analyses.

RESULTS

Eighty-nine per cent of the 5-10-year-old boys and girls had the recommended meal frequency at follow-up. Living in a single-parent family at baseline increased the risk of not eating the recommended number of meals compared with those living in intact families. After adjustments, a mother's low level of education (OR 0.51, CI 0.29-0.93) and a decrease in income sufficiency (OR 0.54, CI 0.35-0.84) during the follow-up period were unfavourably associated with the recommended meal frequency. The difference between children in stable single-parent, reconstituted or joint physical custody families and those living in stable intact families remained significant when controlling for other variables.

CONCLUSIONS

Single-parent families with a low socioeconomic position represent important target groups for interventions designed to promote regular meal frequency.

Effect of a Multidomain Lifestyle Intervention on Estimated Dementia Risk

We investigated the effect of a multidomain lifestyle intervention on the risk of dementia estimated using the validated CAIDE risk score (post-hoc analysis). The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) is a 2-year randomized controlled trial among 1,260 at-risk older adults (60-77 years). Difference in the estimated mean change in CAIDE score at 2 years in the intervention compared to the control group was -0.16 (95 %CI -0.31 to 0.00) (p = 0.013), corresponding to a relative dementia risk reduction between 6.04-6.50%. This could be interpreted as a reflection of the prevention potential of the intervention.

Telomere Length Change in a Multidomain Lifestyle Intervention to Prevent Cognitive Decline: A Randomized Clinical Trial

Background

Shorter leukocyte telomere length (LTL) is associated with aging and dementia. Impact of lifestyle changes on LTL, and relation to cognition and genetic susceptibility for dementia, has not been investigated in randomized controlled trials (RCTs).

Methods

Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability is a 2-year RCT enrolling 1260 participants at risk for dementia from the general population, aged 60–77 years, randomly assigned (1:1) to multidomain lifestyle intervention or control group. The primary outcome was cognitive change (Neuropsychological Test Battery z-score). Relative LTL was measured using quantitative real-time polymerase chain reaction (trial registration: NCT01041989).

Results

This exploratory LTL substudy included 756 participants (377 intervention, 379 control) with baseline and 24-month LTL measurements. The mean annual LTL change (SD) was −0.016 (0.19) in the intervention group and −0.023 (0.17) in the control group. Between-group difference was nonsignificant (unstandardized β-coefficient 0.007, 95% CI −0.015 to 0.030). Interaction analyses indicated better LTL maintenance among apolipoprotein E (APOE)-ε4 carriers versus noncarriers: 0.054 (95% CI 0.007 to 0.102); younger versus older participants: −0.005 (95% CI −0.010 to −0.001); and those with more versus less healthy lifestyle changes: 0.047 (95% CI 0.005 to 0.089). Cognitive intervention benefits were more pronounced among participants with better LTL maintenance for executive functioning (0.227, 95% CI 0.057 to 0.396) and long-term memory (0.257, 95% CI 0.024 to 0.489), with a similar trend for Neuropsychological Test Battery total score (0.127, 95% CI −0.011 to 0.264).

Conclusions

This is the first large RCT showing that a multidomain lifestyle intervention facilitated LTL maintenance among subgroups of older people at risk for dementia, including APOE-ε4 carriers. LTL maintenance was associated with more pronounced cognitive intervention benefits.

Clinical Trials Registration Number

NCT01041989

Earlier life leisure-time physical activity in relation to age-related frailty syndrome

BACKGROUND

frailty syndrome is common amongst older people. Low physical activity is part of frailty, but long-term prospective studies investigating leisure-time physical activity (LTPA) during the life course as a predictor of frailty are still warranted. The aim of this study is to investigate whether earlier life LTPA predicts frailty in older age.

METHODS

the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) included older adults (aged 60-77 years) from the general population who were at increased risk of cognitive decline. Frailty was assessed for 1,137 participants at a baseline visit using a modified version of Fried's phenotype, including five criteria: weight loss, exhaustion, weakness, slowness and low physical activity. Self-reported data on earlier life LTPA were available from previous population-based studies (average follow-up time 13.6 years). A binomial logistic regression analysis was used to investigate the association between earlier life LTPA and pre-frailty/frailty in older age.

RESULTS

the prevalence of frailty and pre-frailty was 0.8% and 27.3%, respectively. In the analyses, pre-frail and frail groups were combined. People who had been physically very active (OR 0.37, 95% CI 0.23-0.60) or moderately active (OR 0.45, 95% CI 0.32-0.65) earlier in life had lower odds of becoming pre-frail/frail than individuals who had been sedentary.

CONCLUSIONS

frailty was rare in this relatively healthy study population, but almost a third of the participants were pre-frail. Earlier life LTPA was associated with lower levels of pre-frailty/frailty. The results highlight the importance of physical activity when aiming to promote healthy old age.

White Matter Changes on Diffusion Tensor Imaging in the FINGER Randomized Controlled Trial

Background:

Early pathological changes in white matter microstructure can be studied using the diffusion tensor imaging (DTI). It is not only important to study these subtle pathological changes leading to cognitive decline, but also to ascertain how an intervention would impact the white matter microstructure and cognition in persons at-risk of dementia.

Objectives:

To study the impact of a multidomain lifestyle intervention on white matter and cognitive changes during the 2-year Finnish Geriatric Intervention Study to prevent Cognitive Impairment and Disability (FINGER), a randomized controlled trial in at-risk older individuals (age 60–77 years) from the general population.

Methods:

This exploratory study consisted of a subsample of 60 FINGER participants. Participants were randomized to either a multidomain intervention (diet, exercise, cognitive training, and vascular risk management, n = 34) or control group (general health advice, n = 26). All underwent baseline and 2-year brain DTI. Changes in fractional anisotropy (FA), diffusivity along domain (F1) and non-domain (F2) diffusion orientations, mean diffusivity (MD), axial diffusivity (AxD), radial diffusivity (RD), and their correlations with cognitive changes during the 2-year multidomain intervention were analyzed.

Results:

FA decreased, and cognition improved more in the intervention group compared to the control group (p < 0.05), with no significant intergroup differences for changes in F1, F2, MD, AxD, or RD. The cognitive changes were significantly positively related to FA change, and negatively related to RD change in the control group, but not in the intervention group.

Conclusion:

The 2-year multidomain FINGER intervention may modulate white matter microstructural alterations.

Effect of the Apolipoprotein E Genotype on Cognitive Change During a Multidomain Lifestyle Intervention: A Subgroup Analysis of a Randomized Clinical Trial

Importance

The role of the apolipoprotein E (APOE) ε4 allele as an effect modifier in lifestyle interventions to prevent cognitive impairment is still unclear.

Objective

To examine whether the APOE ε4 allele modifies the previously reported significant cognitive benefits of a multidomain lifestyle intervention (prespecified subgroup analysis).

Design, Setting, and Participants

The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) was a randomized clinical trial in 6 centers across Finland (screening and randomization performed from September 7, 2009, through November 24, 2011; intervention duration, 2 years). Data analysis was performed from August 1, 2015, to March 31, 2016. The study population was at-risk older individuals from the general population. Inclusion criteria were age of 60 to 77 years; Cardiovascular Risk Factors, Aging, and Dementia risk score of at least 6 points; and cognition at a mean level or slightly lower than expected for age. Individuals with dementia or substantial cognitive impairment and conditions that prevented cooperation or safe engagement in the intervention were excluded. APOE genotype data were available for 1175 of the 1260 participants.

Interventions

Participants were randomly assigned in a 1:1 ratio to a multidomain intervention group (diet, exercise, cognitive training, and vascular risk management) or a control group (general health advice). Group allocation was not actively disclosed to participants, and outcome assessors were masked to group allocation.

Main Outcomes and Measures

Primary outcome was change in cognition measured through a comprehensive neuropsychological test battery. Analysis was based on modified intention to treat (participants with at least 1 postbaseline assessment).

Results

A total of 1109 participants (mean [SD] age, 69.3 [4.7] years; 514 [46.3%] female) were included in the analysis: 362 APOE ε4 allele carriers (173 intervention and 189 control) and 747 noncarriers (380 intervention and 367 control). The APOE ε4 carriers and noncarriers were not significantly different at baseline (except for serum cholesterol level). The difference between the intervention and control groups in annual neuropsychological test battery total score change was 0.037 (95% CI, 0.001 to 0.073) among carriers and 0.014 (95% CI, -0.011 to 0.039) among noncarriers. Intervention effect was not significantly different between carriers and noncarriers (0.023; 95% CI, -0.021 to 0.067).

Conclusions and Relevance

Healthy lifestyle changes may be beneficial for cognition in older at-risk individuals even in the presence of APOE-related genetic susceptibility to dementia. Whether such benefits are more pronounced in APOE ε4 carriers compared with noncarriers should be further investigated. The findings also emphasize the importance of early prevention strategies that target multiple modifiable risk factors simultaneously.

Trial Registration

ClinicalTrials.gov Identifier: NCT01041989.

Brain volumes and cortical thickness on MRI in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER)

Background

The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) was a multicenter randomized controlled trial that reported beneficial effects on cognition for a 2-year multimodal intervention (diet, exercise, cognitive training, vascular risk monitoring) versus control (general health advice). This study reports exploratory analyses of brain MRI measures.

Methods

FINGER targeted 1260 older individuals from the general Finnish population. Participants were 60–77 years old, at increased risk for dementia but without dementia/substantial cognitive impairment. Brain MRI scans were available for 132 participants (68 intervention, 64 control) at baseline and 112 participants (59 intervention, 53 control) at 2 years. MRI measures included regional brain volumes, cortical thickness, and white matter lesion (WML) volume. Cognition was assessed at baseline and 1- and 2-year visits using a comprehensive neuropsychological test battery. We investigated the (1) differences between the intervention and control groups in change in MRI outcomes (FreeSurfer 5.3) and (2) post hoc sub-group analyses of intervention effects on cognition in participants with more versus less pronounced structural brain changes at baseline (mixed-effects regression models, Stata 12).

Results

No significant differences between the intervention and control groups were found on the changes in MRI measures. Beneficial intervention effects on processing speed were more pronounced in individuals with higher baseline cortical thickness in Alzheimer’s disease signature areas (composite measure of entorhinal, inferior and middle temporal, and fusiform regions). The randomization group × time × cortical thickness interaction coefficient was 0.198 (p = 0.021). A similar trend was observed for higher hippocampal volume (group × time × hippocampus volume interaction coefficient 0.1149, p = 0.085).

Conclusions

The FINGER MRI exploratory sub-study did not show significant differences between the intervention and control groups on changes in regional brain volumes, regional cortical thicknesses, or WML volume after 2 years in at-risk elderly without substantial impairment. The cognitive benefits on processing speed of the FINGER intervention may be more pronounced in individuals with fewer structural brain changes on MRI at baseline. This suggests that preventive strategies may be more effective if started early, before the occurrence of more pronounced structural brain changes.

Trial registration

ClinicalTrials.gov, NCT01041989. Registered January 5, 2010.

The Effect of Multidomain Lifestyle Intervention on Daily Functioning in Older People

OBJECTIVE

To investigate the effect of a 2-year multidomain lifestyle intervention on daily functioning of older people.

DESIGN

A 2-year randomized controlled trial (ClinicalTrials.gov, NCT01041989).

SETTING

Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability.

PARTICIPANTS

A total of 1260 older adults, with a mean age of 69 years at the baseline, who were at risk of cognitive decline.

INTERVENTION

A multidomain intervention, including simultaneous physical activity intervention, nutritional counseling, vascular risk monitoring and management, and cognitive training and social activity.

MEASUREMENTS

The ability to perform daily activities (activities of daily living [ADLs] and instrumental ADLs) and physical performance (Short Physical Performance Battery).

RESULTS

The mean baseline ADL score was 18.1 (SD = 2.6) points; the scale ranges from 17 (no difficulties) to 85 (total ADL dependence). During the 2-year intervention, the ADL disability score slightly increased in the control group, while in the intervention group, it remained relatively stable. Based on the latent growth curve model, the difference in the change between the intervention and control groups was -0.95 (95% confidence interval [CI] = -1.61 to -0.28) after 1 year and -1.20 (95% CI = -2.02 to -0.38) after 2 years. In terms of physical performance, the intervention group had a slightly higher probability of improvement (from score 3 to score 4; P = .041) and a lower probability of decline (from score 3 to scores 0-2; P = .043) for chair rise compared to the control group.

CONCLUSION

A 2-year lifestyle intervention was able to maintain the daily functioning of the at-risk older population. The clinical significance of these results in this fairly well-functioning population remains uncertain, but the study results hold promise that healthy eating, exercise, and cognitive and social activity may have favorable effects on functional independence in older people.

Dietary changes and cognition over 2 years within a multidomain intervention trial-The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER)

INTRODUCTION

Association between healthy diet and better cognition is well established, but evidence is limited to evaluate the effect of dietary changes adopted in older age.

METHODS

We investigated the role of dietary changes in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) with 1260 at-risk participants (60-77 years) who were randomized to intensive multidomain intervention (including dietary counseling) or regular health advice for 2 years. Parallel process latent growth curves of adherence to dietary recommendations and cognitive performance were analyzed.

RESULTS

Adherence to healthy diet at baseline predicted improvement in global cognition, regardless of intervention allocation (P = .003). Dietary improvement was associated with beneficial changes in executive function, especially in the intervention group (P = .008; P = .051 for groups combined).

DISCUSSION

Dietary changes initiated during the intervention were related to changes in executive function in 2 years. Long-term diet appeared more influential for global cognition.

Effect of Higher vs Standard Dosage of Vitamin D3 Supplementation on Bone Strength and Infection in Healthy Infants: A Randomized Clinical Trial

IMPORTANCE

Although guidelines for vitamin D supplementation in infants have been widely implemented, they are mostly based on studies focusing on prevention of rickets. The optimal dose for bone strength and infection prevention in healthy infants remains unclear.

OBJECTIVE

To determine whether daily supplementation with 1200 IU of vitamin D3 increases bone strength or decreases incidence of infections in the first 2 years of life compared with a dosage of 400 IU/d.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial involving a random sample of 975 healthy term infants at a maternity hospital in Helsinki, Finland. Study recruitment occurred between January 14, 2013, and June 9, 2014, and the last follow-up was May 30, 2016. Data analysis was by the intention-to-treat principle.

INTERVENTIONS

Randomization of 489 infants to daily oral vitamin D3 supplementation of 400 IU and 486 infants to 1200 IU from age 2 weeks to 24 months.

MAIN OUTCOMES AND MEASURES

Primary outcomes were bone strength and incidence of parent-reported infections at 24 months.

RESULTS

Of the 975 infants who were randomized, 485 (49.7%) were girls and all were of Northern European ethnicity. Eight hundred twenty-three (84.4%) completed the 24-month follow-up. We found no differences between groups in bone strength measures, including bone mineral content (mean difference, 0.4 mg/mm; 95% CI, -0.8 to 1.6), mineral density (mean difference, 2.9 mg/cm3; 95% CI, -8.3 to 14.2), cross-sectional area (mean difference, -0.9 mm2; 95% CI, -5.0 to 3.2), or polar moment of inertia (mean difference, -66.0 mm4, 95% CI, -274.3 to 142.3). Incidence rates of parent-reported infections did not differ between groups (incidence rate ratio, 1.00; 95% CI, 0.93-1.06). At birth, 914 of 955 infants (95.7%) were vitamin D sufficient (ie, 25-hydroxyvitamin D [25(OH)D] concentration ≥20.03 ng/mL). At 24 months, mean 25(OH)D concentration was higher in the 1200-IU group than in the 400-IU group (mean difference, 12.50 ng/mL; 95% CI, 11.22-13.78).

CONCLUSIONS AND RELEVANCE

A vitamin D3 supplemental dose of up to 1200 IU in infants did not lead to increased bone strength or to decreased infection incidence. Daily supplementation with 400 IU vitamin D3 seems adequate in maintaining vitamin D sufficiency in children younger than 2 years.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01723852.

Baseline Telomere Length and Effects of a Multidomain Lifestyle Intervention on Cognition: The FINGER Randomized Controlled Trial

Leukocyte telomere length (LTL) is a biomarker of aging, and it is associated with lifestyle. It is currently unknown whether LTL is associated with the response to lifestyle interventions. The goal is to assess whether baseline LTL modified the cognitive benefits of a 2-year multidomain lifestyle intervention (exploratory analyses). The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) was a 2-year randomized controlled trial including 1,260 people at risk of cognitive decline, aged 60–77 years identified from the general population. Participants were randomly assigned to the lifestyle intervention (diet, exercise, cognitive training, and vascular risk management) and control (general health advice) groups. Primary outcome was change in cognition (comprehensive neuropsychological test battery). Secondary outcomes were changes in cognitive domains: memory, executive functioning, and processing speed. 775 participants (392 control, 383 intervention) had baseline LTL (peripheral blood DNA). Mixed effects regression models with maximum likelihood estimation were used to analyze change in cognition as a function of randomization group, time, baseline LTL, and their interaction. Intervention and control groups did not significantly differ at baseline. Shorter LTL was related to less healthy baseline lifestyle. Intervention benefits on executive functioning were more pronounced among those with shorter baseline LTL (p-value for interaction was 0.010 adjusted for age and sex, and 0.007 additionally adjusted for baseline lifestyle factors). The FINGER intervention cognitive benefits were more pronounced with shorter baseline LTL, particularly for executive functioning, indicating that the multidomain lifestyle intervention was especially beneficial among higher-risk individuals.

Associations of CAIDE Dementia Risk Score with MRI, PIB-PET measures, and cognition

Background:

CAIDE Dementia Risk Score is the first validated tool for estimating dementia risk based on a midlife risk profile.

Objectives:

This observational study investigated longitudinal associations of CAIDE Dementia Risk Score with brain MRI, amyloid burden evaluated with PIB-PET, and detailed cognition measures.

Methods:

FINGER participants were at-risk elderly without dementia. CAIDE Risk Score was calculated using data from previous national surveys (mean age 52.4 years). In connection to baseline FINGER visit (on average 17.6 years later, mean age 70.1 years), 132 participants underwent MRI scans, and 48 underwent PIB-PET scans. All 1,260 participants were cognitively assessed (Neuropsychological Test Battery, NTB). Neuroimaging assessments included brain cortical thickness and volumes (Freesurfer 5.0.3), visually rated medial temporal atrophy (MTA), white matter lesions (WML), and amyloid accumulation.

Results:

Higher CAIDE Dementia Risk Score was related to more pronounced deep WML (OR 1.22, 95% CI 1.05–1.43), lower total gray matter (β-coefficient –0.29, p = 0.001) and hippocampal volume (β-coefficient –0.28, p = 0.003), lower cortical thickness (β-coefficient –0.19, p = 0.042), and poorer cognition (β-coefficients –0.31 for total NTB score, –0.25 for executive functioning, –0.33 for processing speed, and –0.20 for memory, all p < 0.001). Higher CAIDE Dementia Risk Score including APOE genotype was additionally related to more pronounced MTA (OR 1.15, 95% CI 1.00–1.30). No associations were found with periventricular WML or amyloid accumulation.

Conclusions:

The CAIDE Dementia Risk Score was related to indicators of cerebrovascular changes and neurodegeneration on MRI, and cognition. The lack of association with brain amyloid accumulation needs to be verified in studies with larger sample sizes.

Neonatal Nutrition Predicts Energy Balance in Young Adults Born Preterm at Very Low Birth Weight

Epidemiological studies and animal models suggest that early postnatal nutrition and growth can influence adult health. However, few human studies have objective recordings of early nutrient intake. We studied whether nutrient intake and growth during the first 9 weeks after preterm birth with very low birth weight (VLBW, <1500 g) predict total energy intake, resting energy expenditure (REE), physical activity and food preferences in young adulthood. We collected daily nutritional intakes and weights during the initial hospital stay from hospital records for 127 unimpaired VLBW participants. At an average age 22.5 years, they completed a three-day food record and a physical activity questionnaire and underwent measurements of body composition (dual X-ray absorptiometry; n = 115 with adequate data) and REE (n = 92 with adequate data). We used linear regression and path analysis to investigate associations between neonatal nutrient intake and adult outcomes. Higher energy, protein and fat intakes during the first three weeks of life predicted lower relative (=per unit lean body mass) energy intake and relative REE in adulthood, independent of other pre- and neonatal factors. In path analysis, total effects of early nutrition and growth on relative energy intake were mostly explained by direct effects of early life nutrition. A path mediated by early growth reached statistical significance only for protein intake. There were no associations of neonatal intakes with physical activity or food preferences in adulthood. As a conclusion, higher intake of energy and nutrients during first three weeks of life of VLBW infants predicts energy balance after 20 years. This association is partly mediated through postnatal growth.

A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial

BACKGROUND

Modifiable vascular and lifestyle-related risk factors have been associated with dementia risk in observational studies. In the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER), a proof-of-concept randomised controlled trial, we aimed to assess a multidomain approach to prevent cognitive decline in at-risk elderly people from the general population.

METHODS

In a double-blind randomised controlled trial we enrolled individuals aged 60-77 years recruited from previous national surveys. Inclusion criteria were CAIDE (Cardiovascular Risk Factors, Aging and Dementia) Dementia Risk Score of at least 6 points and cognition at mean level or slightly lower than expected for age. We randomly assigned participants in a 1:1 ratio to a 2 year multidomain intervention (diet, exercise, cognitive training, vascular risk monitoring), or a control group (general health advice). Computer-generated allocation was done in blocks of four (two individuals randomly allocated to each group) at each site. Group allocation was not actively disclosed to participants and outcome assessors were masked to group allocation. The primary outcome was change in cognition as measured through comprehensive neuropsychological test battery (NTB) Z score. Analysis was by modified intention to treat (all participants with at least one post-baseline observation). This trial is registered at ClinicalTrials.gov, number NCT01041989.

FINDINGS

Between Sept 7, 2009, and Nov 24, 2011, we screened 2654 individuals and randomly assigned 1260 to the intervention group (n=631) or control group (n=629). 591 (94%) participants in the intervention group and 599 (95%) in the control group had at least one post-baseline assessment and were included in the modified intention-to-treat analysis. Estimated mean change in NTB total Z score at 2 years was 0·20 (SE 0·02, SD 0·51) in the intervention group and 0·16 (0·01, 0·51) in the control group. Between-group difference in the change of NTB total score per year was 0·022 (95% CI 0·002-0·042, p=0·030). 153 (12%) individuals dropped out overall. Adverse events occurred in 46 (7%) participants in the intervention group compared with six (1%) participants in the control group; the most common adverse event was musculoskeletal pain (32 [5%] individuals for intervention vs no individuals for control).

INTERPRETATION

Findings from this large, long-term, randomised controlled trial suggest that a multidomain intervention could improve or maintain cognitive functioning in at-risk elderly people from the general population.

FUNDING

Academy of Finland, La Carita Foundation, Alzheimer Association, Alzheimer's Research and Prevention Foundation, Juho Vainio Foundation, Novo Nordisk Foundation, Finnish Social Insurance Institution, Ministry of Education and Culture, Salama bint Hamdan Al Nahyan Foundation, Axa Research Fund, EVO funding for University Hospitals of Kuopio, Oulu, and Turku and for Seinäjoki Central Hospital and Oulu City Hospital, Swedish Research Council, Swedish Research Council for Health, Working Life and Welfare, and af Jochnick Foundation.

Associations between parental BMI, socioeconomic factors, family structure and overweight in Finnish children: a path model approach

Background

The aim of this study was to assess the less studied interrelationships and pathways between parental BMI, socioeconomic factors, family structure and childhood overweight.

Methods

The cross-sectional LATE-study was carried out in Finland in 2007–2009. The data for the analyses was classified into four categories: younger boys and girls (ca 3–8 years) (n = 2573) and older boys and girls (ca 11–16 years) (n = 1836). Associations between parental BMI, education, labor market status, self-perceived income sufficiency, family structure and childhood overweight were first examined by logistic regression analyses. As parental BMI and education had the most consistent associations with childhood overweight, the direct and indirect (mediated by parental BMI) associations of maternal and paternal education with childhood overweight were further assessed using a path model.

Results

Parental BMI and education were the strongest determinants of childhood overweight. Children of overweight parents had an increased risk of being overweight. In younger boys, maternal and paternal education had both direct (b-coefficient paternal −0.21, 95% CI −0.34 to −0.09; maternal −0.17, 95% CI −0.28 to −0.07) and indirect (b-coefficient paternal −0.04, 95% CI −0.07 to −0.02; maternal −0.04, 95% CI −0.06 to −0.02) inverse associations with overweight. Among the older boys, paternal education had both direct (b-coefficient −0.12, 95% CI −0.24 to −0.01) and indirect (b-coefficient −0.03, 95% CI −0.06 to −0.01) inverse associations with overweight, but maternal education had only an indirect association (b-coefficient −0.04, 95% CI −0.07 to −0.02). Among older girls, only an indirect association of maternal education with childhood overweight was found (b-coefficient −0.03, 95% CI −0.06 to −0.01). In younger girls, parental education was not associated with childhood overweight.

Conclusion

The observed pathways between parental BMI and education and childhood overweight emphasize a need for evidence-based health promotion interventions tailored for families identified with parental overweight and low level of education.

Family characteristics and health behaviour as antecedents of school nurses' concerns about adolescents' health and development: a path model approach

BACKGROUND

Family socio-economic factors and parents' health behaviours have been shown to have an impact on the health and well-being of children and adolescents. Family characteristics have also been associated with school nurses' concerns, which arose during health examinations, about children's and adolescents' physical health and psychosocial development. Parental smoking has also been associated with smoking in adolescents.

OBJECTIVES

The aim of this study was to determine to what extent school nurses' concerns about adolescents' physical health and psychosocial development related to family characteristics are mediated through parents' and adolescents' own health behaviours (smoking).

DESIGN

A path model approach using cross-sectional data was used.

SETTINGS

In 2008-2009, information about health and well-being of adolescents was gathered at health examinations of the Children's Health Monitoring Study.

PARTICIPANTS

Altogether 1006 eighth and ninth grade pupils in Finland participated in the study.

METHODS

The associations between family characteristics, smoking among parents and adolescents and school nurses' concerns about adolescents' physical health and psychosocial development were examined using a structural equation model.

RESULTS

Paternal education had a direct, and, through fathers' and boys' smoking, an indirect association with school nurses' concerns about the physical health of boys. Paternal labour market status and family income were only indirectly associated with concerns about the physical health of boys by having an effect on boys' smoking through paternal smoking, and a further indirect effect on concerns about boys' health. In girls, only having a single mother was strongly associated with school nurses' concerns about psychosocial development through maternal and adolescent girl smoking.

CONCLUSIONS

Socio-economic family characteristics and parental smoking influence adolescent smoking and are associated with school nurses' concerns about adolescents' physical health and psychosocial development. The findings underline the importance of comprehensively taking into account adolescents' and parents' health behaviours and the family situation in health-care contacts when providing health counselling.

Prevalence, predictors and covariates of functional status impairment among Finnish Second World War veterans during 1992-2004

BACKGROUND

the functional status is one of the most important health measurements in the elderly. This study aimed to investigate the prevalence of self-reported physical and mental conditions among Finnish Second World War veterans during 1992-2004. We also aimed to study the ability of these conditions in 1992 to predict the functional status impairment in 2004 and to determine whether the worsening of symptoms or the onset of new diseases during 1992-2004 was associated with impaired basic activities of daily living (BADL) and instrumental activities of daily living (IADL) in 2004.

METHODS

the study population was 4,999 veterans living in Finland participating in both the Veteran Project 1992 and 2004. Logistic regression models were employed to identify predictors for impaired BADL and IADL. Analyses were conducted separately for men with and without disability and for women.

RESULTS

the highest risk estimate for impaired BADL in 2004 was in men without disability who had a neurological disease in 1992 [odds ratios (OR): 5.78, 95% CI: 2.49-13.43], in men with disability with walking difficulties in 1992 (OR: 2.41, 95% CI: 1.79-3.25) and in women with a musculoskeletal disease in 1992 (OR: 2.39, 95% CI: 1.58-3.62). For impaired IADL, walking difficulties had the highest risk estimate in all veteran groups.

CONCLUSION

mental and physical conditions, especially walking difficulties, can predict veterans' future functional impairment even 12 years in advance, and worsening of these conditions is associated with impaired ADL.

Externalizing behaviors and cigarette smoking as predictors for use of illicit drugs: a longitudinal study among Finnish adolescent twins

We examined whether externalizing problem behaviors (hyperactivity-impulsivity, aggressiveness, and inattention) predict illicit drug use independently, or whether their associations with drug use are mediated through cigarette smoking. We used a prospective longitudinal design within the FinnTwin12-17 study among Finnish adolescents with baseline at age 12 and follow-up surveys at ages 14 and 17. Path models were conducted with Mplus and included 1992 boys and 2123 girls. The outcome was self-reported ever use of cannabis or other illicit drugs at age 17. The predictors were: externalizing behaviors (hyperactivity-impulsivity, aggressiveness, and inattention) assessed by teachers and parents (age 12) and self-reported cigarette smoking (age 14). The findings differed across behavior studied. The association of hyperactivity-impulsivity with drug use was mostly mediated through earlier cigarette smoking. Concerning aggressiveness and inattention, the results were different among girls than boys. Among girls no significant mediation occurred, whereas among boys more consistent evidence on mediation was seen. Consistently in all models, the direct association of early cigarette smoking on drug use was strong and highly significant. We conclude that the associations of externalizing problem behaviors with illicit drug use are partially mediated through cigarette smoking. Although interventions targeting externalizing problem behaviors may protect adolescents from early onset smoking and subsequently experimenting with drugs, interventions to prevent cigarette smoking initiation are also important in reducing risk of later drug use.

Tobacco, cannabis, and other illicit drug use among Finnish adolescent twins: causal relationship or correlated liabilities?

OBJECTIVE

Among Finnish adolescent twins, we compared (a) a model that describes a direct impact of liability to tobacco use on cannabis and other illicit drug use with (b) a model that included a shared underlying liability for these substances. Furthermore, the extent to which genetic and environmental influences contribute to the covariation between liabilities to use these substances was examined.

METHOD

Tobacco and illicit drug use were assessed at age 17.5 years. Twin data on 3,744 individuals were analyzed using standard biometrical methods. Two alternative multivariate models were fi t and compared with Mx, a statistical program for genetic model fitting.

RESULTS

The multivariate model, including a direct impact of the initiation of tobacco use on illicit drug use, provided the best fit to the data. In this model, the total variation in the initiation of illicit drugs was decomposed to genetic factors (32%), common environmental factors (20%), unique environmental factors (8%), and a component due to initiation of smoking (40%). Most variation in the progression of illicit drug use was the result of initiation of smoking and illicit drug use (83%).

CONCLUSIONS

Liability to initiate smoking directly affects illicit drug use in our best-fitting model. Our findings suggest that several common genetic influences may be related to tobacco use and illicit drugs but that a search for specific genes underlying illicit drug use is justifi ed as well. Such specific genes may hold a key to understanding biological vulnerabilities that lead to illicit drug use, which could aid in the development of targeted interventions.

Evidence that BMI and type 2 diabetes share only a minor fraction of genetic variance: a follow-up study of 23,585 monozygotic and dizygotic twins from the Finnish Twin Cohort Study

AIMS/HYPOTHESIS

We investigated whether BMI predicts type 2 diabetes in twins and to what extent that is explained by common genetic factors.

METHODS

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.

RESULTS

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.

CONCLUSIONS/INTERPRETATION

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.

Associations of 25 structural, degradative, and inflammatory candidate genes with lumbar disc desiccation, bulging, and height narrowing

OBJECTIVE

To examine the allelic diversity of structural, inflammatory, and matrix-modifying gene candidates and their association with disc degeneration.

METHODS

Subjects were 588 men ages 35-70 years. We investigated associations of single-nucleotide polymorphisms in AGC1 and in 12 collagen, 8 interleukin, and 4 matrix metalloproteinase genes with quantitative magnetic resonance imaging measurements of disc desiccation and disc bulging and height narrowing scores, after controlling for age and suspected risk factors. Analyses were performed using QTDT software. P values were derived from 1,000 permutations, and empirical P values for global significance also were applied.

RESULTS

Twelve of the 99 variants in 25 selected candidate genes provided evidence of association (P < 0.05) with disc signal intensity in the upper and/or lower lumbar regions. Allelic variants of AGC1 (rs1042631; P = 0.001), COL1A1 (rs2075555; P = 0.005), COL9A1 (rs696990; P = 0.00008), and COL11A2 (rs2076311; P = 0.018) genes provided the most significant evidence of association with disc signal intensity. The same variants of AGC1 (P = 0.010) and COL9A1 (P = 0.014), as well as variants in the COL11A1 gene (rs1463035 [P = 0.004]; rs1337185 [P = 0.015]) were also associated with disc bulging, as was AGC1 with disc height narrowing (rs1516797; P = 0.005). In addition, 4 allelic variants in the immunologic candidate genes (rs2071375 in IL1A [P = 0.027]; rs1420100 in IL18RAP [P = 0.005]) were associated with disc signal intensity.

CONCLUSION

Genetic variants account for interindividual differences in disc matrix synthesis and degradation. The accuracy of the quantitative disc signal intensity measurements we used likely enhanced our ability to observe these associations. Our findings shed light on possible mechanisms of degeneration and support the view that disc degeneration is a polygenetic condition.

Characteristics and health consequences of intermittent smoking: long-term follow-up among Finnish adult twins

INTRODUCTION

The definition of a smoker as someone who smokes daily has been challenged. No consensus exists regarding whether intermittent smoking represents transition toward daily smoking or cessation or whether intermittent smokers consistently maintain their low tobacco use frequency. Although abundant evidence supports the adverse health consequences of daily smoking, less evidence is available on intermittent smoking.

METHODS

We examined characteristics and health consequences of intermittent cigarette smoking among Finnish adult twins. We used longitudinal data of 21,340 persons with smoking status from questionnaires in 1975 and 1981 and data on lung cancer incidence from 1982 to 2004 from the Finnish Cancer Registry.

RESULTS

We identified 641 consistent intermittent smokers comprising 3% of the study population. Consistent intermittent smokers had higher education, less use of other tobacco products, healthier lifestyles, and partly more favorable mental health profiles compared with lifetime regular smokers. However, in terms of other lifestyle factors, intermittent smokers compared mostly unfavorably with never-smokers, despite being better educated. Intermittent smoking showed substantial heritability. There were 213 incident lung cancer cases among all study subjects; only one case was found among the intermittent smokers. The sex- and age-adjusted hazard ratios of lung cancer were not significantly elevated for the intermittent smokers, but they were increased more than 10-fold for all other smokers.

DISCUSSION

Although the present study did not find evidence of elevated lung cancer risk among intermittent smokers, compared with never-smokers, further studies should investigate other health consequences of intermittent smoking, such as cardiovascular and nonmalignant pulmonary outcomes.

Genetic and environmental effects on disc degeneration by phenotype and spinal level: a multivariate twin study

STUDY DESIGN

A classic twin study with multivariate analyses was conducted.

OBJECTIVE

We aimed to further clarify the presence and magnitude of genetic influences on disc degeneration, and to better understand the phenomenon of disc degeneration through comparisons of genetic and environmental influences on specific degenerative signs and different lumbar levels.

SUMMARY OF BACKGROUND DATA

Previous studies suggest a substantial genetic influence on disc degeneration, but raise important questions about which disc phenotypes are or are not largely genetically influenced and differential effects on spinal levels.

METHODS

The study sample consisted of 152 monozygotic and 148 dizygotic male twin pairs, 35 to 70 years of age, from the population-based Finnish Twin Cohort. Lumbar magnetic resonance imaging was conducted with quantitative or qualitative assessments of disc signal, bulging, and height narrowing at each lumbar level. Data on possible confounding factors were obtained from an extensive, structured interview. Quantitative genetic modeling was conducted using MPlus.

RESULTS

Heritability estimates varied from 29% to 54%, depending on the particular disc degeneration phenotype and lumbar level. The same genetic influences affected signal intensity and disc height (genetic correlations of -0.60- -0.66) or bulging (-0.71- -0.72) to a great degree at either the lower or upper lumbar levels and genetic influences on disc height narrowing and bulging were virtually the same. (0.92-0.97). Conversely, genetic correlations (and environmental correlations)were substantially lower for upper and lower lumbar levels, implying largely independent effects.

CONCLUSION

Genetic and environmental influences on disc degeneration seem to be of similar importance. Disc signal, narrowing, and bulging had a primarily common genetic pathway, suggesting a common genetic etiopathogenesis. Conversely, genetic and environmental influences differed substantially for upper versus lower lumbar levels, emphasizing the importance of examining these levels separately in studies of associated genes, other constitutional factors, and environmental influences.

The genetic liability to disability retirement: a 30-year follow-up study of 24,000 Finnish twins

Background

No previous studies on the effect of genetic factors on the liability to disability retirement have been carried out. The main aim of this study was to investigate the contribution of genetic factors on disability retirement due to the most common medical causes, including depressive disorders.

Methods

The study sample consisted of 24 043 participants (49.7% women) consisting of 11 186 complete same-sex twin pairs including 3519 monozygotic (MZ) and 7667dizygotic (DZ) pairs. Information on retirement events during 1.1.1975–31.12.2004, including disability pensions (DPs) with diagnoses, was obtained from the Finnish nationwide official pension registers. Correlations in liability for MZ and DZ twins and discrete time correlated frailty model were used to investigate the genetic liability to age at disability retirement.

Results

The 30 year cumulative incidence of disability retirement was 20%. Under the best fitting genetic models, the heritability estimate for DPs due to any medical cause was 0.36 (95% CI 0.32–0.40), due to musculoskeletal disorders 0.37 (0.30–0.43), cardiovascular diseases 0.48 (0.39–0.57), mental disorders 0.42 (0.35–0.49) and all other reasons 0.24 (0.17–0.31). The effect of genetic factors decreased with increasing age of retirement. For DP due to depressive disorders, 28% of the variance was explained by environmental factors shared by family members (95% CI 21–36) and 58% of the variance by the age interval specific environmental factors (95% CI 44–71).

Conclusions

A moderate genetic contribution to the variation of disability retirement due to any medical cause was found. The genetic effects appeared to be stronger at younger ages of disability retirement suggesting the increasing influence of environmental factors not shared with family members with increasing age. Familial aggregation in DPs due to depressive disorders was best explained by the common environmental factors and genetic factors were not needed to account for the pattern of familial aggregation.

Heritability of BMD of femoral neck and lumbar spine: a multivariate twin study of Finnish men

Of the 80% variation in BMD among male twins that is caused by genetics, part was explained by genetic influences on lifting strength and lean body mass/height. Lifting strength was significant in both the femoral and spine BMD and body weight only for lumbar BMD.

INTRODUCTION

The dominant role of heritability in BMD has been shown in twin studies among women. However, the mechanisms of genetic influences are poorly understood. BMD is associated with lean body mass and muscle strength, which both have a genetic component, but the relative effects of muscle strength and lean body mass/height on the total genetic and environmental variations influencing BMD of men are unclear.

MATERIALS AND METHODS

Measurements of BMD from a DXA scanner on a representative sample of 147 monozygotic and 153 dizygotic male twin pairs (age, 35-70 yr) were related to a variety of anthropometric and behavioral covariates and interview data. Data were analyzed with univariate modeling of genetic characteristics, bivariate modeling of covariates that were significant in univariate models, and multivariate modeling of the simultaneous effects of significant covariates from the bivariate models.

RESULTS

Heritability influences were estimated to account for 75% of the variance in femoral BMD and 83% in lumbar BMD. Univariate and bivariate modeling showed that, of the factors studied, only lifting force and lean body mass/height had statistically significant influences. Of the total genetic variation in femoral BMD, lifting force explained 9%, and lean body mass/height 18%; the proportions for lumbar BMD were 9% and 11%, respectively. Of the total environmental variation, the correlation with isokinetic lifting force explained 9% for femoral BMD and 10% for lumbar BMD. The genetic correlations between lifting force and femoral and lumbar BMD were approximately 0.3, as were the environmental correlations of isokinetic lifting force and femoral and lumbar BMD and of lean body mass/height and femoral BMD. The environmental correlation of lean body mass/height and femoral BMD was not significant.

CONCLUSIONS

Lifting force had effects on both femoral and lumbar BMD. Body weight was important, but only for lumbar BMD. Muscle strength may have the best potential for modification among behavioral factors to increase both femoral and lumbar BMD.

Role of genetic and environmental influences on heart rate variability in middle-aged men

Our aim was to estimate causal relationships of genetic factors and different specific environmental factors in determination of the level of cardiac autonomic modulation, i.e., heart rate variability (HRV), in healthy male twins and male twins with chronic diseases. The subjects were 208 monozygotic (MZ, 104 healthy) and 296 dizygotic (DZ, 173 healthy) male twins. A structured interview was used to obtain data on lifetime exposures of occupational loading, regularly performed leisure-time sport activities, coffee consumption, smoking history, and chronic diseases from 12 yr of age through the present. A 5-min ECG at supine rest was recorded for the HRV analyses. In univariate statistical analyses based on genetic models with additive genetic, dominance genetic, and unique environmental effects, genetic effects accounted for 31–57% of HRV variance. In multivariate statistical analysis, body mass index, percent body fat, coffee consumption, smoking, medication, and chronic diseases were associated with different HRV variables, accounting for 1–11% of their variance. Occupational physical loading and leisure-time sport activities did not account for variation in any HRV variable. However, in the subgroup analysis of healthy and diseased twins, occupational loading explained 4% of the variability in heart periods. Otherwise, the interaction between health status and genetic effects was significant for only two HRV variables. In conclusion, genetic factors accounted for a major portion of the interindividual differences in HRV, with no remarkable effect of health status. No single behavioral determinant appeared to have a major influence on HRV. The effects of medication and diseases may mask the minimal effect of occupational loading on HRV.

The effects of anthropometrics, lifting strength, and physical activities in disc degeneration

STUDY DESIGN

A cross-sectional study design was used.

OBJECTIVE

The objective was to examine the influences of body anthropometrics, axial disc area, and lifting strength on disc degeneration and to compare these with the effects of lifetime physical demands and age.

SUMMARY OF BACKGROUND DATA

Although recent studies have shown that heredity is a dominant factor in disc degeneration, the common notion that occupational physical loading is the major risk factor persists. However, substantial variations in disc degeneration, particularly at the lowest lumbar levels, remain unexplained by heredity or occupational physical demands.

METHODS

Univariate methods and stepwise multiple regression modeling were used to estimate associations of body height, weight, fat content, axial disc area, isokinetic lifting performance, and lifetime routine physical activities at work and leisure with disc height narrowing and disc signal (in T2 images) based on lumbar MRIs. These data were available from a population sample of 600 men, 35 to 70 years of age.

RESULTS

Lower disc signal, representing disc desiccation, was associated with higher age, lower body mass and lifting strength, and larger axial disc area. Of the variance in disc signal, age explained 8.0% (P < 0.001) and body weight/axial disc area, isokinetic lifting strength, and occupational lifting history added 3.9%, 2.3%, and 1.3%, respectively. Greater disc narrowing was associated with higher age, larger axial disc area, and higher occupational physical loading. Of the variance in disc narrowing, age accounted for 3.8% (P < 0.001); axial disc area and occupational loading added 1.9% (P < 0.004) and 1.3% (P < 0.007), respectively.

CONCLUSIONS

Body weight, lifting strength, and axial disc area were more highly associated with disc degeneration than occupational and leisure physical activity histories, although all had modest influences. Furthermore, higher body mass, greater lifting strength, and heavier work were all associated with more disc height narrowing but less disc desiccation contrary to current views. Smaller discs appeared to have beneficial effects.

Relative roles of heredity and physical activity in adolescence and adulthood on blood pressure

Part of the association between physical activity and low blood pressure (BP) may be a consequence of genetic selection. We investigated the association of genetic factors and physical activity in adolescence and adulthood with BP. BP was measured with a Finapres device in 71 monozygotic and 104 dizygotic male twin pairs using no antihypertensive medication. Subjects' mean age was 50.4 yr (range 40–72 yr). Subjects were interviewed about their lifetime exercise and other health habits. Exercise was classified as aerobic, power, or other, and these were further divided into adolescence (12–20 yr of age), the previous year, and lifetime. Genetic modeling was conducted to estimate genetic and environmental components of variance of systolic and diastolic BP. Aerobic exercise in adolescence and high-intensity aerobic exercise throughout the lifetime were associated with low diastolic BP in adulthood. Of the variance in diastolic BP, genetic factors accounted for 35% and aerobic exercise in adolescence for 5%. For systolic BP, genetic factors accounted for 39% of the variance. In turn, genetic factors accounted for 44% of the variance in aerobic exercise in adolescence. The genetic factors in part accounting for the variance in diastolic BP and those in part accounting for variance in aerobic exercise in adolescence were correlated. The association between aerobic exercise in adolescence and low diastolic BP in adulthood is a new finding, as is the observation that the factors partly share the same genes.

Multivariate genetic analysis of lifetime exercise and environmental factors

PURPOSE

We investigated whether the association between exercise and individual-specific factors that correlate with exercise may be explained by genetic or common environmental factors.

METHODS

Lifetime exercise data were available from 147 MZ and 153 DZ adult male twin pairs with a mean age of 50 yr (SD = 8 yr).

RESULTS

The best-fitting quantitative genetic model for adulthood exercise level consisted of additive genetic effects, genetic effects due to dominance and unique environment effects, with genetic effects explaining 51% (95% CI = 29-63%) of the variance. Factors associated with adulthood exercise level were adolescent exercise, participation in competitive sports, perceived health, smoking status, and percent body fat. In bivariate models, approximately half of the covariation between those factors and adulthood exercise level was accounted for by unique environmental effects (i.e., factors not shared by the co-twins). Additive genetic effects explained less (3-20%) than dominance genetic effects (23-53%) of the covariation between those factors and adulthood exercise. Shared environmental effects were present only in the bivariate model of adulthood and adolescent exercise, explaining 11% of the covariance.

CONCLUSIONS

: The genetic component shared in common by exercise and factors associated with exercise suggests that there may be a complex pathway of genetic selection and predisposition for a physically active lifestyle.

The role of genetics and environment in lifting force and isometric trunk extensor endurance

BACKGROUND AND PURPOSE

Our understanding of what different back performance tests are measuring is limited. The purpose of this study was to investigate the relative contributions of genetics and unique and common environmental factors for 3 tests of back muscle performance in a classic twin analysis.

SUBJECTS

The subjects were a population-based sample of 122 monozygotic and 131 dizygotic male twin pairs aged 35 to 69 years (mean=49.9, SD=7.7).

METHODS

Variance component analysis was applied to estimate genetic and environmental influences on isokinetic and psychophysical lifting and isometric trunk extensor endurance test performance. The Cholesky decomposition genetic factor model was used to estimate genetic and environmental correlations of these variables. Path analysis was applied to study determinants of isokinetic and psychophysical lifting and isometric trunk extensor endurance test performance.

RESULTS

Genetic effects accounted for 60%, 33%, and 5% of the total variance of isokinetic and psychophysical lifting forces and isometric trunk extensor endurance, respectively, and unique environmental factors accounted for 35%, 49%, and 61% of the variance.

DISCUSSION AND CONCLUSION

Genetics had a dominant role in isokinetic lifting and unique environmental factors in isometric trunk extensor endurance. The relatively high role of genetics in lifting force suggests the potential to increase and sustain changes in back muscle force in the general population may be particularly challenging.

Factors associated with exercise lifestyle--a study of monozygotic twins

Regular exercise is widely advocated for a broad range of health issues. Yet, the association of familial factors (i. e. both genetic and childhood environmental factors) and specific environmental factors (not shared by family members) as well as health behavior with lifelong exercise participation is currently poorly understood. A total of 117 monozygotic male twin pairs aged 35 - 69 y (mean age 49 y), recruited from the population-based Finnish Twin Cohort, were studied. A summary outcome exercise variable was created by calculating the mean hours of exercise per week from 18 y of age to present from data provided from a structured interview. Suspected factors associated with exercise were analyzed with linear regression, while pairwise relationships were analysed using polychoric correlations and structural equation modeling. There was substantial familial aggregation in adulthood exercise, accounting for 43 % of all variation in exercise using the LISREL model. Factors associated with enhanced adherence to exercise in adulthood were participation in exercise and competitive sports in adolescence (from age 12 to 18). Education, age, number of chronic diseases, smoking, alcohol use, marital status, number of children and number of changes in residence were not associated with exercise adherence in adulthood. Our results suggest that early childhood environmental factors strongly influence exercise level throughout the lifespan. Therefore, interventions aimed at enhancing lifelong exercise participation may achieve more beneficial long-term results by targeting families and other childhood and adolescent environments.

Repeatability of lifetime exercise reporting

The purpose of the study was to determine the reliability of lifetime exercise data obtained through a structured interview. Interviews were conducted in 1992-1993 and repeated in 1997 in 150 monozygotic male twins, aged 35-69 years, from the population-based Finnish Twin Cohort. Exercise mode, frequency, duration, intensity and period of participation were solicited for each regularly performed exercise from 12 years of age to the present. Questions related to the most common exercise mode reported in the initial interview were repeated in all subjects and the entire exercise interview was repeated in a subgroup of 38 subjects. The repeatability was highest for exercise years and mean hours/ week by mode for the most commonly performed exercise (Mean ICC=0.63-0.90), and for the sum of all lifetime exercises reported (Mean ICC = 0.69-0.73). The lowest repeatability was found for exercise intensity (Mean Kappa = 0.33-0.48). Similarly poor reliability was found for whether or not exercise was performed at a competitive level (Mean Kappa = 0.25-0.63). Overall, the structured interview of lifetime exercise was most repeatable for years of exercise and mean hours/week. Thus, these exposure variables should be considered in retrospective studies of exercise effects.

Perceived tiredness among adolescents and its association with sleep habits and use of psychoactive substances

This study investigated the variation in perceived tiredness among 11, 13 and 15-year-old Finnish adolescents (n = 4187). Additionally interrelationships between sleep habits, use of psychoactive substances (alcohol, tobacco and coffee) and perceived tiredness among 15-year-olds were examined. This study is part of an international, WHO-coordinated survey of school children's health and lifestyle (the HBSC Study). In Finland, research data represented the whole country. The data were collected in March-May 1994. Pupils responded anonymously to a standardized questionnaire during a class period. Subjective tiredness was very common and increased with age among adolescents. Perceived tiredness on at least four school mornings a week increased from 24 to 35% among boys and from 16 to 34% among girls. Feeling tired more often than once a week increased from 20 to 37% in girls and from 24 to 50% in boys. Structural equation models showed that interrelationships between three factors--sleep habits, use of psychoactive substances and perceived tiredness--were statistically significant. For these three factors the two remaining factors explained 24% of the variance of perceived tiredness among boys and 20% among girls, and the two remaining factors explained 42% (16%) of the variation in sleep habits. For the variance of the use of psychoactive substances sleep habits and perceived tiredness explained 26% (12%). Subjective tiredness is strongly age related; this together with the use of psychoactive substances and sleep habits regulate adolescents' daily life and well-being.