10.3.2008

Boshuizen, H. C., Lanti, M., Menotti, A., Moschandreas, J., Tolonen, H., Nissinen, A., Nedeljkovic, S., Kafatos, A. and Kromhout, D.

American Journal of Epidemiology. 2008; 167(4). Letter. IF 5.241

Smoking reduction predicts cessation: Longitudinal evidence from the Finnish adult twin cohort

Broms, U., Korhonen, T. and Kaprio, J.

Nicotine Tob Res. 2008; 10(3): 423-7. IF 2.299

The aim of the study was to examine whether smoking reduction over a 6-year period (1975-1981) predicted smoking cessation 9 years later by 1990.

The longitudinal data from three surveys over 15-year period among the Finnish adult twin cohort were used. The data were collected by postal surveys in 1975, 1981, and 1990, and the sample comprised 11,015 participants, of whom 2,443 were persistent current smokers in 1975 and 1981. Smoking cessation by 1990 was examined as the outcome measure.

Nineteen percent reported having stopped smoking by 1990, corresponding to an approximate annual rate of smoking cessation of 2%. Those who had quit smoking by 1990 had larger decreases in smoking between 1975 and 1981. The odds ratio for quitting by 1990 increased with increasing levels of reduction in amount smoked between 1975 and 1981. This was found in both categorical and trend analyses, and when adjusting for age, sex and for amount of baseline smoking. The model among twin pairs discordant for cessation indicated that the association of smoking reduction with increased likelihood of cessation was independent of genetic or early shared family influences on smoking behavior.

We conclude that smokers who are able to decrease the number of cigarettes smoked per day by at least 25% are more likely to quit later.

Independent introduction of two lactase-persistence alleles into human populations reflects different history of adaptation to milk culture

Enattah, N. S., Jensen, T. G. K., Nielsen, M., Lewinski, R., Kuokkanen, M., Rasinpera, H., El-Shanti, H., Seo, J. K., Alifrangis, M., Khalil, I. F., Natah, A., Ali, A., Natah, S., Comas, D., Mehdi, S. Q., Groop, L., Vestergaard, E. M., Imtiaz, F., Rashed, M. S., Meyer, B., Troelsen, J. and Peltonen, L.

American Journal of Human Genetics. 2008; 82(1): 57-72. Article. IF 12.629

The T-13910 variant located in the enhancer element of the lactase (LCT) gene correlates perfectly with lactase persistence (LP) in Eurasian populations whereas the variant is almost nonexistent among Sub-Saharan African populations, showing high prevalence of LP.

Here, we report identification of two new mutations among Saudis, also known for the high prevalence of LP. We confirmed the absence of the European T-13910 and established two new mutations found as a compound allete: T/G(-13915) within the -13910 enhancer region and a synonymous SNP in the exon 17 of the MCM6 gene T/C-3712, -3712 bp from the LCT gene. The compound allele is driven to a high prevalence among Middle East population(s). Our functional analyses in vitro showed that both SNPs of the compound allele, located 10 kb apart, are required for the enhancer effect, most probably mediated through the binding of the hepatic nuclear factor 1 alpha (HNF1 alpha). High selection coefficient (s) similar to 0.04 for LP phenotype was found for both T-13910 and the compound allele. The European T-13910 and the earlier identified East African G(-13907) LP allele share the same ancestral background and most likely the same history, probably related to the same cattle domestication event. In contrast, the compound Arab allele shows a different, highly divergent ancestral haplotype, suggesting that these two major global LP alleles have arisen independently, the latter perhaps in response to camel milk consumption.

These results support the convergent evolution of the LP in diverse populations, most probably reflecting different histories of adaptation to milk culture.

Simkania negevensis in community-acquired pneumonia in Italian children

Fasoli, L., Paldanius, M., Don, M., Valent, F., Vetrugno, L., Korppi, M. and Canciani, M.

Scandinavian Journal of Infectious Diseases. 2008; 40(3): 269-272. Article. IF 1.560

Simkania negevensis, a recently found Chlamydia-like organism, has been associated with respiratory infections in children and adults with pneumonia, but S. negevensis findings have been common also without any infection.

The aims of the present paper were to evaluate S. negevensis in the aetiology of paediatric community-acquired pneumonia (CAP), its seroprevalence in north Italian children, and whether there is cross-reactivity between S. negevensis and Chlamydia pneumoniae serology. Antibodies to S. negevensis were measured by microimmunofluorescence (MIF) in 101 frozen paired sera obtained from children with CAP. Serological evidence (>/=4-fold increase or decrease in IgM or IgG) of acute S. negevensis infection was achieved in 5 (5%) cases. Two were mixed infections with Mycoplasma pneumoniae and 1 with respiratory syncytial virus. In total, 20-30% of the children had measurable antibodies to S. negevensis, with no association with age.

No cross-reactivity was observed between antibodies to S. negevensis and C. pneumoniae. S. negevensis appears to be a real, though rare, cause of CAP in children.

Changes in traditional risk factors no longer explain time trends in cardiovascular mortality and its socioeconomic differences

Harald, K., Koskinen, S., Jousilahti, P., Torppa, J., Vartiainen, E. and Salomaa, V.

Journal of Epidemiology and Community Health. 2008; 62(3): 251-257. Article. IF 2.805

Aim: To investigate to what extent the changes in traditional risk factors (total cholesterol, smoking, hypertension) explain the changes in socioeconomic (defined by occupational class and household income) differences in cardiovascular mortality in Finland during the past 20 years.

Design: Study population comprised 14 642 men and women aged 35-64 years who were selected from population-based FINRISK surveys in 1987, 1992, 1997 or 2002 in three areas of Finland. The 1982 and 1987 FINRISK cohorts were used to determine a model for the probability of cardiovascular death based on risk factor values at the baseline for each socioeconomic group. These predicted changes in cardiovascular mortality were then contrasted with observed mortality rates in different socioeconomic groups to determine the contribution of the changes in risk factors to changes in actual mortality.

Results: We found that among men during 1987-97, when risk factor levels were improving in all socioeconomic groups, the model explained 29-44% of the observed mortality decline. The risk factors explained a larger part of the decline among lower socioeconomic groups. During the period 1997-2002 the risk factor levels stopped improving in all socioeconomic groups but observed mortality rates kept declining. The predicted mortality rates were 16-34% of the observed rates during the period 1987-2002.

Conclusions: Changes in traditional risk factors no longer provide a good explanation of the changes in cardiovascular mortality and its socioeconomic differences. However, risk factors did explain the cardiovascular mortality decline among lower socioeconomic groups.

Simkania negevensis may be a true cause of community acquired pneumonia in children

Heiskanen-Kosma, T., Paldanius, M. and Korppi, M.

Scandinavian Journal of Infectious Diseases. 2008; 40(2): 127-130. Article. IF 1.560

Simkania negevensis, a recently found Chlamydia-like organism, has been associated with bronchiolitis and pneumonia in children. S. negevensis findings have been common also in healthy, non-symptomatic subjects. Antibodies to S. negevensis were measured by microimmunofluorescence in 174 frozen paired sera obtained from children with community acquired pneumonia in a population-based study. There was evidence of S. negevensis infection in 18 (10%) cases. All diagnoses were based on the presence of specific IgM antibodies. The numbers of S. negevensis cases increased from 2 (4%) at < 24 months to 7 (15%) at >= 10 y of age. 12 (67%) were mixed infections with viruses or other bacteria. 16 children (9%) had measurable IgG antibodies to S. negevensis, but significant rises were not found in any cases. Thus, S. negevensis may be a real, though rare, cause of CAP in children, occurring often in mixed infections with viruses and other bacteria.

DISC1 association, heterogeneity and interplay in schizophrenia and bipolar disorder

Hennah, W., Thomson, P., McQuillin, A., Bass, N., Loukola, A., Anjorin, A., Blackwood, D., Curtis, D., Deary, I. J., Harris, S. E., Isometsa, E. T., Lawrence, J., Lonnqvist, J., Muir, W., Palotie, A., Partonen, T., Paunio, T., Pylkko, E., Robinson, M., Soronen, P., Suominen, K., Suvisaari, J., Thirumalai, S., Clair, D. S., Gurling, H., Peltonen, L. and Porteous, D.

Mol Psychiatry. 2008. IF 11.804

Disrupted in schizophrenia 1 (DISC1) has been associated with risk of schizophrenia, schizoaffective disorder, bipolar disorder, major depression, autism and Asperger syndrome, but apart from in the original translocation family, true causal variants have yet to be confirmed.

Here we report a harmonized association study for DISC1 in European cohorts of schizophrenia and bipolar disorder. We identify regions of significant association, demonstrate allele frequency heterogeneity and provide preliminary evidence for modifying interplay between variants. Whereas no associations survived permutation analysis in the combined data set, significant corrected associations were observed for bipolar disorder at rs1538979 in the Finnish cohorts (uncorrected P=0.00020; corrected P=0.016; odds ratio=2.73+/-95% confidence interval (CI) 1.42-5.27) and at rs821577 in the London cohort (uncorrected P=0.00070; corrected P=0.040; odds ratio=1.64+/-95% CI 1.23-2.19). The rs821577 single nucleotide polymorphism (SNP) showed evidence for increased risk within the combined European cohorts (odds ratio=1.27+/-95% CI 1.07-1.51), even though significant corrected association was not detected (uncorrected P=0.0058; corrected P=0.28). After conditioning the European data set on the two risk alleles, reanalysis revealed a third significant SNP association (uncorrected P=0.00050; corrected P=0.025). This SNP showed evidence for interplay, either increasing or decreasing risk, dependent upon the presence or absence of rs1538979 or rs821577.

These findings provide further support for the role of DISC1 in psychiatric illness and demonstrate the presence of locus heterogeneity, with the effect that clinically relevant genetic variants may go undetected by standard analysis of combined cohorts.Molecular Psychiatry advance online publication, 4 March 2008; doi:10.1038/mp.2008.22.

Antibody responses to defined regions of the Bordetella pertussis virulence factor pertactin

Hijnen, M., He, Q., Schepp, R., Van Gageldonk, P., Mertsola, J., Mooi, F. R. and Berbers, G. A. M.

Scandinavian Journal of Infectious Diseases. 2008; 40(2): 94-104. Article. IF 1.560

Although vaccines against Bordetella pertussis, the causative agent of whooping cough, have been in use for over 50 y, the disease has remained endemic and is still a public health problem in many countries.

It has been shown that antibody titres against pertactin, which is 1 of the exposed virulence factors of pertussis, correlate with protection and pertactin is now 1 of the components of most acellular pertussis vaccines. However, little is known about the structure and location of protective epitopes on pertactin. Here we set out to investigate the antibody response using naturally occurring pertactin variants and deletion derivates. We found the N-terminus of pertactin to be immunodominant in both rabbits and humans.

In contrast to vaccinated rabbits, we could not detect pertactin type-specific antibodies in human sera. In conclusion, these results show for the first time to which defined regions of the pertactin molecule antibody responses are induced. It also suggests that the amount of pertactin type-specific antibodies will not be very large and that the variation in pertactin probably will not constitute a problem in highly immune individuals.

Effects of solubility of urban air fine and coarse particles on cytotoxic and inflammatory responses in RAW 264.7 macrophage cell line

Jalava, P. I., Salonen, R. O., Pennanen, A. S., Happo, M. S., Penttinen, P., Halinen, A. I., Sillanpaa, M., Hillamo, R. and Hirvonen, M. R.

Toxicol Appl Pharmacol. 2008. IF 4.722

We investigated the inflammatory and cytotoxic activities of the water-soluble and -insoluble as well as organic-solvent-soluble and -insoluble fractions of urban air fine (PM(2.5-0.2)) and coarse (PM(10-2.5)) particulate samples.

The samples were collected with a high volume cascade impactor (HVCI) in 7-week sampling campaigns of selected seasons in six European cities. Mouse macrophage cells (RAW 264.7) were exposed to the samples for 24 h. The production of nitric oxide (NO) and proinflammatory cytokines (TNFalpha, IL-6), and cytotoxicity (MTT-test, apoptosis, cell cycle) were measured. The inflammatory and cytotoxic responses in both size ranges were mostly associated with the insoluble particulate fractions.

However, both the water- and organic-solvent-soluble particulate fractions induced TNFalpha production and apoptosis and had some other cytotoxic effects. Soil-derived water-soluble and -insoluble components of the chemical PM(2.5-0.2) mass closure had consistent positive correlations with the responses, while the correlations were negative with the secondary inorganic anions (NO(3)(-), NH(4)(+), non-sea-salt SO(4)(2-)) and particulate organic matter (POM). With the PM(10-2.5) samples, sea salt and soluble soil components correlated positively with the induced toxic responses. In this size range, a possible underestimation of the insoluble, soil-related compounds containing Si and Ca, and biological components of POM, increased uncertainties in the evaluation of associations of the mass closure components with the responses.

It is concluded that insoluble components of the complex urban air particulate mixture exert the highest inflammatory and cytotoxic activities in the macrophage cell line but, at the same time, they may operate as carriers for active water- and lipid-soluble components.

The dilemma of patient responsibility for lifestyle change: perceptions among primary care physicians and nurses

Jallinoja, P., Absetz, P., Kuronen, R., Nissinen, A., Talja, M., Uutela, A. and Patja, K.

Scand J Prim Health Care. 2007; 25(4): 244-9. IF 1.541

OBJECTIVE: To explore physicians' and nurses' views on patient and professional roles in the management of lifestyle-related diseases and their risk factors.

DESIGN: A questionnaire study with a focus on adult obesity, dyslipidemia, high blood pressure, type 2 diabetes, and smoking.

SETTING: Healthcare centres in Paijat-Hame hospital district, Finland.

SUBJECTS: Physicians and nurses working in primary healthcare (n =220).

MAIN OUTCOME MEASURES: Perceptions of barriers to treatment of lifestyle-related conditions, perceptions of patients' responsibilities in self-care, experiences of awkwardness in intervening in obesity and smoking, perceptions of rushed schedules, and perceptions of health professionals' roles and own competence in lifestyle counselling.

RESULTS: A majority agreed that a major barrier to the treatment of lifestyle-related conditions is patients' unwillingness to change their habits. Patients' insufficient knowledge was considered as such a barrier less often. Self-care was actively encouraged. Although a majority of both physicians and nurses agreed that providing information, and motivating and supporting patients in lifestyle change are part of their tasks, only slightly more than one half estimated that they have sufficient skills in lifestyle counselling. Among nurses, those with less professional experience more often reported having sufficient skills than those with more experience. Two-thirds of the respondents reported that they had been able to help many patients to change their lifestyles into healthier ones.

CONCLUSIONS: The primary care professionals experienced a dilemma in patients' role in the treatment of lifestyle-related diseases: the patient was recognized as central in disease management but also, if reluctant to change, a major potential barrier to treatment.

Invasive infections caused by Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae among children in St Petersburg, Russia

Kaijalainen, T., Kharit, S. M., Kvetnaya, A. S., Sirkia, K., Herva, E., Parkov, O. V. and Nohynek, H.

Clin Microbiol Infect. 2008. IF 3.254

This study investigated the causes of invasive bacterial infections in children aged <15 years in St Petersburg, Russia, during 2001-2003, using culture and antigen detection methods (rapid antigen latex agglutination (RAL)) for normally sterile body fluids. A pathogen was detected in 90 cases (culture 50, RAL 40). Neisseria meningitidis was the most common pathogen (66%), followed by Haemophilus influenzae (19%) and Streptococcus pneumoniae (16%). Meningitis was the main clinical diagnosis (68/90, 76%), with N. meningitidis serogroup B, H. influenzae type b (Hib), and S. pneumoniae serogroup 1 being the most common isolates. Hib was less prevalent in St Petersburg than it was in industrialised countries before the introduction of Hib vaccinations.

Differences in the clinical characteristics of adolescent depressive disorders

Karlsson, L., Pelkonen, M., Heila, H., Holi, M., Kiviruusu, O., Tuisku, V., Ruuttu, T. and Marttunen, M.

Depress Anxiety. 2007; 24(6): 421-32. IF 2.549

Our objective was to analyze differences in clinical characteristics and comorbidity between different types of adolescent depressive disorders.

A sample of 218 consecutive adolescent (ages 13-19 years) psychiatric outpatients with depressive disorders was interviewed for DSM-IV Axis I and Axis II diagnoses. We obtained data by interviewing the adolescents themselves and collecting additional background information from the clinical records. Lifetime age of onset for depression, current episode duration, frequency of suicidal behavior, psychosocial impairment, and the number of current comorbid psychiatric disorders varied between adolescent depressive disorder categories. The type of co-occurring disorder was mainly consistent across depressive disorders. Minor depression and dysthymia (DY) presented as milder depressions, whereas bipolar depression (BPD) and double depression [DD; i.e., DY with superimposed major depressive disorder (MDD)] appeared as especially severe conditions. Only earlier lifetime onset distinguished recurrent MDD from first-episode MDD, and newly emergent MDD appeared to be as impairing as recurrent MDD. Adolescent depressive disorder categories differ in many clinically relevant aspects, with most differences reflecting a continuum of depression severity. Identification of bipolarity and the subgroup with DD seems especially warranted. First episode MDD should be considered as severe a disorder as recurring MDD.

Characterizing the generalized lambda distribution by L-moments

Karvanen, J. and Nuutinen, A.

Computational Statistics & Data Analysis. 2008; 52(4): 1971-1983. Article. IF 0.928

The generalized lambda distribution (GLD) is a flexible four parameter distribution with many practical applications. L-moments of the GLD can be expressed in closed form and are good alternatives for the central moments.

The L-moments of the GLD up to an arbitrary order are presented, and a study of L-skewness and L-kurtosis that can be achieved by the GLD is provided. The boundaries of L-skewness and L-kurtosis are derived analytically for the symmetric GLD and calculated numerically for the GLD in general. Additionally, the contours of L-skewness and L-kurtosis are presented as functions of the GLD parameters. It is found that with an exception of the smallest values of L-kurtosis, the GLD covers all possible pairs of L-skewness and L-kurtosis and often there are two or more distributions that share the same L-skewness and the same L-kurtosis. Examples that demonstrate situations where there are four GLD members with the same L-skewness and the same L-kurtosis are presented. The estimation of the GLD parameters is studied in a simulation example where method of L-moments compares favorably to more complicated estimation methods.

The results increase the knowledge on the distributions that belong to the GLD family and can be utilized in model selection and estimation. (C) 2007 Elsevier B.V. All rights reserved.

Marked temporal increase in the incidence of type 1 and type 2 diabetes among young adults in Finland

Lammi, N., Blomstedt, P. A., Moltchanova, E., Eriksson, J. G., Tuomilehto, J. and Karvonen, M.

Diabetologia. 2008. IF 5.247

Correct identification and discrimination between Campylobacter jejuni and C. coli by a standardized hippurate test and species-specific polymerase chain reaction

Nakari, U. M., Puhakka, A. and Siitonen, A.

Eur J Clin Microbiol Infect Dis. 2008. IF 2.330

Hippurate hydrolysis test results of 240 Campylobacter strains were compared with those of two multiplex polymerase chain reaction (PCR) assays. Of the 152 strains identified in Finnish clinical microbiology routine laboratories as C. coli (hippurate-negative), 11% were C. jejuni (hippurate-positive) by standardized hippurate test and 39% by PCR in the reference laboratory. Two of the 81 hippurate-positive strains were identified as C. coli.

Standardizing the hippurate test by determining minimum and maximum turbidity limits (McFarland 6 and McFarland 10, OD(450) values 0.8 and 1.4, respectively) for the bacterial cell suspension eliminated the false-positive results, but 32% of the 145 hippurate-negative strains were still identified as C. jejuni by PCR. The species identification of Campylobacter isolates in Finland could be improved by using a standardized hippurate hydrolysis test to identify hippurate-positive C. jejuni and testing hippurate-negative strains by molecular methods.

This would also improve the epidemiological data on this important zoonotic pathogen.

Dietary intake and major food sources of polyphenols in Finnish adults

Ovaskainen, M. L., Torronen, R., Koponen, J. M., Sinkko, H., Hellstrom, J., Reinivuo, H. and Mattila, P.

Journal of Nutrition. 2008; 138(3): 562-566. Article. IF 4.009

Phenolic acids, flavonoids, proanthocyanidins, and ellagitannins are polyphenols that may have beneficial effects on human health and provide protection against chronic diseases. To date, limited data exist on quantitative intake of polyphenols.

The aims of this study were to estimate the quantitative intakes of polyphenols by using analyzed concentrations together with individual food consumption records and to determine major dietary sources. Analyzed concentrations of phenolic acids, anthocyanidins, and other flavonoids, proanthocyanicins, and ellagitannins (44 total polyphenol compounds) were entered into the national food composition database, Fineli.

The absolute intakes of the polyphenols and the corresponding food sources were calculated on the basis of 48-h dietary recalls of 2007 Finnish adults. The mean total intake of polyphenols was 863 +/- 415 mg/d. Phenolic acids comprised the dominant group of polyphenols (75% of total intake) followed by proanthocyanidins (14%) and anthocyanidins and other flavonoids (10%). Due to their high consumption and high concentrations of phenolic acids, coffee and cereals were the main contributors to total polyphenol intake. Berries and berry products were the main source for anthocyanidins, ellagitannins, and proanthocyanidins, and fruits were the main source for flavonols, flavones, and flavanones.

The results give additional support to the recommendations for a varied diet with fruits, berries, cereals, and vegetables.

National immunization program in Finland

Rapola, S.

Int J Circumpolar Health. 2007; 66(5): 382-9.

In the national immunization program, all Finnish children are vaccinated against 9 infectious diseases: diphtheria, tetanus, pertussis, polio, severe infections due to Haemophilus influenzae type b, measles, mumps, rubella and influenza.

In addition, vaccination against tuberculosis, hepatitis A- and B-, influenza or tick-borne encephalitis are given to those at risk of contracting the diseases.

More than 95% of children are vaccinated according the optimal schedule. Vaccine preventable diseases are rare in Finland. In Finland, all vaccines are imported. The decisions regarding the vaccination program are made by the Ministry of Social Affairs and Health.

The National Public Health Institute is responsible for the control of the communicable diseases and the implementation of the vaccination program in practice. Evaluation of the implementation of new vaccines in the vaccination program is ongoing.

Low phospholipid transfer protein (PLTP) is a risk factor for peripheral atherosclerosis

Schgoer, W., Mueller, T., Jauhiainen, M., Wehinger, A., Gander, R., Tancevski, I., Salzmann, K., Eller, P., Ritsch, A., Haltmayer, M., Ehnholm, C., Patsch, J. R. and Foeger, B.

Atherosclerosis. 2008; 196(1): 219-226. Article. IF 3.811

Objective: Phospholipid transfer protein (PLTP) facilitates cholesterol efflux from cells, intravascular HDL remodelling and transfer of vitamin E and endotoxin. In humans, the relationship of PUP to atherosclerosis is unknown. However, strong coronary risk factors like obesity, diabetes, cigarette smoking and inflammation increase circulating levels of active PUP. The aim of the present, cross-sectional study was to analyze the relationship of PLTP to peripheral arterial disease, a marker of generalized atherosclerosis, independently of potentially confounding factors like obesity, diabetes and smoking.

Methods: We performed a case control study in 153 patients with symptomatic peripheral arterial disease (PAD) and 208 controls free of vascular disease. Smokers and patients with diabetes mellitus were excluded. A lipoprotein-independent assay was used for measurement of circulating bioactive PLTP and an ELISA utilizing a monoclonal antibody was used to analyze PLTP mass.

Results: PUP activity was significantly decreased in patients with PAD 5.5 (4.6-6.4)(median (25th-75th percentile)) versus 5.9 (5.1-6.9) mu mol/mL/h in controls (p = 0.001). In contrast, PUP mass was similar in patients with PAD 8.5 mu g/mL (7.3-9.5) and in controls 8.3 mu g/mL (6.9-9.7) (p = 0.665). Multivariate logistic regression analysis revealed that PLTP activity is independently associated with the presence of PAD. PLTP activity was similar in patients with and without lipid-lowering drugs (p = 0.396).

Conclusion: Our results show that in non-diabetic, non-smoking subjects low rather than high PLTP activity is a marker for the presence of peripheral arterial disease and that distribution of PUP between high-activity and low-activity forms may be compromised in atherosclerosis. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

Associations between long-term physical activity, waist circumference and weight gain: a 30-year longitudinal twin study

Waller, K., Kaprio, J. and Kujala, U. M.

International Journal of Obesity. 2008; 32(2): 353-361. Article. IF 4.055

Background and objective: Physical activity level and obesity are both partly determined by genes and childhood environment. To determine the associations between long-term leisure-time physical activity, weight gain and waist circumference and whether these are independent of genes and childhood effects.

Design and subjects: The study design is a 30-year follow- up twin study in Finland. For this study, 146 twin pairs were comprehensively identified from the large Finnish Twin Cohort. These twin pairs were discordant for both intensity and volume of leisure physical activity in 1975 and 1981 and were healthy in 1981. At follow- up in 2005, both members of 89 pairs were alive and participated in a structured telephone interview. In the interview self-measured weight and waist circumference, and physical activity level for the whole follow- up were assessed. Paired tests were used in the statistical analyses.

Main outcome measures: Waist circumference at 30-year follow- up (2005) and change in weight from 1975 to 2005. Results: In the 42 twin pairs discordant for physical activity at all time points during the 30-year period, the mean weight gain from 1975 through 2005 was 5.4 kg (95% confidence interval (CI) 2.0-8.9) less in the active compared to inactive co-twins (paired t-test, P = 0.003). In 2005, the mean waist circumference was 8.4 cm (95% CI 4.0-12.7) less in the active compared with inactive co-twins (P < 0.001). These trends were similar for both monozygotic and dizygotic twin pairs. Pairwise differences in weight gain and waist circumference were not seen in the 47 twin pairs, who were not consistently discordant for physical activity.

Conclusion: Persistent participation in leisure-time physical activity is associated with decreased rate of weight gain and with a smaller waist circumference to a clinically significant extent even after partially controlling for genetic liability and childhood environment.

Contribution of non-work and work-related risk factors to the association between income and mental disorders in a working population: the Health 2000 Study

Virtanen, M., Koskinen, S., Kivimäki, M., Honkonen, T., Vahtera, J., Ahola, K. and Lönnqvist, J.

Occupational and Environmental Medicine. 2008; 65(3): 171-178. Article. IF 2.255

Objectives: To examine the contribution of non-work and work factors to the association between income and DSM-IV depressive and anxiety disorders in a working population.

Methods: A representative sample of the Finnish working population aged 30-64 (1667 men, 1707 women) in 2000-2001 responded to a survey questionnaire on non-work factors (marital status, housing conditions, non-work social support, violence victimisation, smoking, physical symptoms), work factors (job demands, job control, social support at work, educational prospects, job insecurity) and household income. Somatic health was examined in a standard health examination. The 12-month prevalence of depressive and anxiety disorders was examined with the Composite International Diagnostic Interview.

Results: The risk of having a depressive or anxiety disorder was 2.8 times higher in the low-income group than in the high-income group among men and 2.0 times higher among women. For men, non- work and work factors explained 20% and 31% of this association, respectively. For women, the corresponding figures were 65% and 23%.

Conclusions: Low income is associated with frequent mental disorders among a working population. In particular, work factors among men and non- work factors among women contribute to the income differences in mental health.