Negative life events predict weight gain in a 13-year follow-up of an adult Swedish population.

BACKGROUND: Increasing psychosocial stress may underlie contemporary obesity trends. We investigate cross-sectional and prospective associations between negative life events (NLEs) and anthropometric indicators, and whether these are explained by lifestyle, depression and sleeping problems. METHODS: Participants in the Swedish INTERGENE cohort answered questions about ten types of NLE, and indicated whether they occurred during the last year or earlier (2001-04, n = 2706). Body mass index (BMI) and waist-to-hip ratio (WHR) were measured at baseline, and at follow-up (2014-16, n = 974). Numbers of recent and distant NLE were related to anthropometric variables using linear models including age, sex, and education, and further adjusted for lifestyle, and psychological problems. Prospective models were adjusted for baseline anthropometric values. RESULTS: Participants reported on average 3.6 types of NLEs, of which 70% were experienced more than one year ago. At baseline, distant but not recent NLEs were associated with higher values of both BMI and WHR. These associations were explained in part by lifestyle and depression assessed at baseline. Recent but not distant NLEs predicted gain in BMI, 0.19 (0.07, 0.30) kg/m2, and WHR, 0.005 (0.002, 0.007), per event and independent of baseline covariates. The largest associations were seen for job insecurity and financial worries, with 0.35 (0.17, 0.52) kg/m2 increase in BMI corresponding to approximately 1.2 kg per event, in both sexes. CONCLUSION: We observed positive associations between NLEs and weight gain over 13 years including signs of latency and recovery regarding adverse weight development.

Negative emotional states and negative life events: Consequences for cardiovascular health in a general population.

OBJECTIVE: The contemporary increase in psychological distress observed in many countries is, by itself, a public health issue of great concern. The present study aims to investigate associations between self-reported negative emotional states and negative life events, and cardiovascular disease (CVD). METHODS: Prospective cohort study based on the Swedish INTERGENE cohort comprising 3614 men and women, aged 25 to 75. Baseline examinations during 2001-2004 included self-rating depression and anxiety scales, life stress, as well as a wide range of physiological and behavioral parameters, which allowed for relevant adjustments. Cox proportion hazard was used to predict incident CVD, CVD mortality as well as all-cause mortality. RESULTS: The results showed a dose-response relationship between depressiveness, anxiety and negative life events on the one hand, and increased risk of CVD. Most of these associations persisted in the fully adjusted models. Furthermore, the youngest age group (25-44 years) generally showed the highest prevalence of psychosocial distress, and also had the highest risks of incident CVD with regard to depression and anxiety. CONCLUSION: The associations between psychological distress and later life cardiovascular disease calls for enhanced public health efforts aiming at ameliorating psychological health, not least in younger age groups.

A within-sibling pair analysis of lifestyle behaviours and BMI z-score in the multi-centre I.Family study.

BACKGROUND AND AIMS: By investigating differences in lifestyle behaviours and BMI in sibling pairs, family-level confounding is minimized and causal inference is improved, compared to cross-sectional studies of unrelated children. Thus, we aimed to investigate within-sibling pair differences in different lifestyle behaviours and differences in BMI z-scores in children and adolescents. METHODS AND RESULTS: We examined three groups of sibling pairs 1) all same-sex sibling pairs with maximum 4 years age difference (n = 1209 pairs from 1072 families in 8 countries, mean age 10.7 years, standard deviation 2.4 years), 2) sibling pairs discordant for overweight (n = 262) and 3) twin pairs (n = 85). Usual dietary intake was estimated by 24-h recalls and time spent in light (LPA) and moderate-to-vigorous physical activity (MVPA) was measured by accelerometers. Screen time, sleep and dieting for weight loss were assessed by questionnaires. Within all 3 groups of sibling pairs, more time in MVPA was associated with lower BMI z-score. Higher energy intake was associated with higher BMI z-score within twin pairs and within all sibling pairs who were not currently dieting for weight loss. Regarding LPA, screen time or sleep duration, no or inconsistent associations were observed for the three groups of sibling pairs. CONCLUSIONS: MVPA and energy intake were associated with BMI differences within sibling and twin pairs growing up in the same home, thus independent of family-level confounding factors. Future studies should explore whether genetic variants regulating appetite or energy expenditure behaviours account for weight differences in sibling pairs.

Lower risk of hip fractures among Swedish women with large hips?

In women, a large hip circumference (HC) related to lower hip fracture risk, independent of age and regardless if HC was measured long before or closer to the fracture. In older women, body mass index (BMI) explained the protection. INTRODUCTION: In postmenopausal women, HC has been suggested to inversely associate with hip fracture while this has not been investigated in middle-aged women. We examined the association between HC, measured at two different time points, and hip fracture in a Swedish female population-based sample monitored for incident hip fractures over many years. METHODS: Baseline HC, measured in 1968 or 1974 (n = 1451, mean age 47.6 years), or the HC measures that were the most proximal before event or censoring (n = 1325, mean age 71.7 years), were used to assess the effects of HC on hip fracture risk in women participating in the Prospective Population Study of Women in Gothenburg. HC was parameterized as quintiles with the lowest quintile (Q1) as reference. Incident hip fractures over 45 years of follow-up (n = 257) were identified through hospital registers. RESULTS: Higher quintiles of HC at both baseline and proximal to event were inversely associated with hip fracture risk in age-adjusted models, but only baseline HC predicted hip fractures independently of BMI and other covariates (HR (95% CI) Q2, 0.85 (0.56-1.27); Q3, 0.59 (0.36-0.96); Q4, 0.57 (0.34-0.96); Q5, 0.58 (0.31-1.10)). CONCLUSIONS: A large HC is protective against hip fracture in midlife and in advanced age, but the association between proximal HC and hip fracture was explained by concurrent BMI suggesting that padding was not the main mechanism for the association. The independent protection seen in middle-aged women points to other mechanisms influencing bone strength.

Blood fatty acid composition in relation to allergy in children aged 2-9 years: results from the European IDEFICS study.

BACKGROUND/OBJECTIVES: Blood polyunsaturated fatty acids (PUFA) are involved in allergy development, but the etiological role of n-6 and n-3 PUFA is still controversial. A European multicenter study of children (IDEFICS) provided the opportunity to explore the cross-sectional association between fatty acids (FA) and allergy. SUBJECTS/METHODS: Blood FA levels were measured in 2600 children aged 2-9 years and were recorded as the percentage of weight of all FA detected. Logistic regression of allergy status on FA components was adjusted for age, sex, country, body mass index, family history of allergic disease, breast-feeding, and number of siblings. The results were given as odds ratios (OR) for current vs no allergy ever and an increase in FA by 1 s.d. RESULTS: Overall, higher proportions of n-6 PUFA were associated with higher odds of allergy (OR=1.21 (1.05, 1.40)). Monounsaturated FA (MUFA) were associated with reduced risk for allergy (OR=0.75 (0.65, 0.87)), whereas saturated FA did not differ by allergy status. The strongest associations were observed in children <4 years old, with ORs of allergy given as 1.62 (1.15, 2.29) for n-3 PUFA and 0.63 (0.42, 0.95) for MUFA. With regard to individual FA, these associations were independently observed for docosapentaenoic acid (22:5 n-3) and oleic acid (18:1 n-9). CONCLUSIONS: Both PUFA subtypes were positively associated with allergy in an age-dependent manner, whereas MUFA was associated with less allergy. The observation of high proportions of n-3 PUFA in allergic children younger than 4 years might help to understand the nature of early onset of atopic disease.

Socioeconomic inequalities in childhood overweight: heterogeneity across five countries in the WHO European Childhood Obesity Surveillance Initiative (COSI-2008).

BACKGROUND: Excess risk of childhood overweight and obesity occurring in socioeconomically disadvantaged families has been demonstrated in numerous studies from high-income regions, including Europe. It is well known that socioeconomic characteristics such as parental education, income and occupation are etiologically relevant to childhood obesity. However, in the pan-European setting, there is reason to believe that inequalities in childhood weight status may vary among countries as a function of differing degrees of socioeconomic development and equity. SUBJECTS AND METHODS: In this cross-sectional study, we have examined socioeconomic differences in childhood obesity in different parts of the European region using nationally representative data from Bulgaria, the Czech Republic, Lithuania, Portugal and Sweden that were collected in 2008 during the first round of the World Health Organization (WHO) European Childhood Obesity Surveillance Initiative. RESULTS: Heterogeneity in the association between parental socioeconomic indicators and childhood overweight or obesity was clearly observed across the five countries studied. Positive as well as negative associations were observed between parental socioeconomic indicators and childhood overweight, with statistically significant interactions between country and parental indicators. CONCLUSIONS: These findings have public health implications for the WHO European Region and underscore the necessity to continue documenting socioeconomic inequalities in obesity in all countries through international surveillance efforts in countries with diverse geographic, social and economic environments. This is a prerequisite for universal as well as targeted preventive actions.

Differential outcome of the IDEFICS intervention in overweight versus non-overweight children: did we achieve 'primary' or 'secondary' prevention?

BACKGROUND: The aim of this study was to explore whether the IDEFICS intervention had a differential effect on 11,041 children's weight trajectories depending on their baseline body mass index status. METHODS: Two subgroups of children are considered in the present analysis: those who were overweight or obese prior to the intervention and those who were neither overweight nor obese. RESULTS: Among children in all eight countries who did not have prevalent overweight or obesity (OWOB) at baseline, 2 years later, there was no significant difference between intervention and control groups in risk of having developed OWOB. However, we observed a strong regional heterogeneity, which could be attributed to the presence of one distinctly outlying country, Belgium, where the intervention group had increased risk for becoming overweight. In contrast, among the sample of children with prevalent OWOB at baseline, we observed a significantly greater probability of normalized weight status after 2 years. In other words, a protective effect against persistent OWOB was observed in children in intervention regions compared with controls, which corresponded to an adjusted odds ratio of 0.76 (95% confidence interval: 0.58, 0.98). DISCUSSION: This analysis thus provided evidence of a differential effect of the IDEFICS intervention, in which children with overweight may have benefited without having been specifically targeted. However, no overall primary preventive effect could be observed in children without initial overweight or obesity.

Body composition by dual-energy X-ray spectrometry and bioelectrical impedance spectroscopy in a healthy population at age 75 and 80.

OBJECTIVE: Bioelectrical impedance spectroscopy (BIS) is a versatile field tool to obtain information about body composition (BC), if prediction equations are available that are valid for the group under consideration. We aimed to validate prediction equations for total body skeletal muscle mass (TBSMM) developed in healthy 75-year olds from the Gothenburg area (Sweden) in a similar sample examined at age 80. We give new prediction equations for fat mass (FM), fat-free mass (FFM), and TBSMM that are based on the entire group of elderly subjects, using values from Dual-energy X-ray spectrometry (DXA) as reference standard. Finally, we describe the longitudinal change in BC in the subset of subjects, who participated at both age 75 and 80. SUBJECTS AND METHODS: Body composition was measured by DXA and multiple-frequency BIS at age 75 (n = 111) and 80 (n = 91) years. Ordinary and mixed linear regression was used to examine previous and new prediction equations. Longitudinal change was assessed by paired sample t-test. RESULTS: The prediction equations for TBSMM developed in 75-year old subjects showed good validity when applied to the sample of 80 year olds. The results were independent of the presence of a metal prosthesis in hip or knee. New, sex-specific prediction equations for FM, FFM, and TBSMM were derived for 75 - 80 year-old subjects that further improved the accuracy of prediction. Using DXA-derived BC at ages 75 and 80, we observed a decline in TBSMM in both sexes, which was mainly due to muscle loss in the legs. In men, the decrease in trunk FFM was accompanied by an increase in FM, leaving no overall weight change in the trunk. When the 5-year change in TBSMM was based on longitudinal BIS measurements, the results from DXA were reproduced only when the prediction was based on BIS-values at 50 kHz. CONCLUSIONS: Good cross-sectional validity of BIS equations for TBSMM was found in a population sample of 80-year olds. The presence of a metal prosthesis did not influence the quality of prediction. New prediction equations for FM, FFM, and TBSMM need to be evaluated in an independent sample.

Extension of nanoconfined DNA: Quantitative comparison between experiment and theory.

The extension of DNA confined to nanochannels has been studied intensively and in detail. However, quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose, we performed experiments measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic strength of the buffer. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths, the agreement is less good. We discuss possible reasons. In principle, our approach allows us to measure the Kuhn length and the effective width of a single DNA molecule and more generally of semiflexible polymers in solution.

The association between plasma homocysteine and coronary heart disease is modified by the MTHFR 677C>T polymorphism.

OBJECTIVE: An elevated level of total plasma homocysteine (tHcy) has been associated with risk of coronary heart disease (CHD). The level of tHcy is affected by lifestyle, in addition to genetic predisposition. The methylene tetrahydrofolate reductase (MTHFR) 677C>T polymorphism (rs1801133) is among the strongest genetic predictors of tHcy. We examined whether the association between tHcy and CHD is modified by the MTHFR 677C>T polymorphism. DESIGN AND SETTING: Data from two case-control studies of first-time myocardial infarction (MI), Stockholm Heart Epidemiology Programme (SHEEP), and for MI and unstable angina, INTERGENE, were analysed in parallel. PATIENTS: THcy was determined in a total of 1150 cases and 1753 controls. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The outcome comprised first-time MI and unstable angina, subsumed as CHD. Logistic regression was used to investigate the association between tHcy and CHD, and its modification by genotype. RESULTS: High tHcy was confirmed to be a risk factor for CHD in both studies. In SHEEP, the association between tHcy and MI was observed in MTHFR 677 C-homozygotes (OR=1.4, 95% CI 1.2 to 1.6, for a difference by 1 SD of log tHcy) and in heterozygotes (OR=1.3, 95% CI 1.1 to 1.6) but not in T-homozygotes, independent of smoking, physical activity and obesity. An effect modification of similar magnitude was observed but not statistically significant in the smaller INTERGENE study, and confirmed in a meta-analysis of both studies. CONCLUSIONS: Two Swedish case-control studies showed that the association between elevated tHcy and CHD was confined to carriers of the MTHFR 677 C-allele, which could have implications for the efficiency of tHcy-lowering treatment.

Secular trends in weight, height and BMI in young Swedes: the 'Grow up Gothenburg' studies.

AIM: This study aims to document secular differences in anthropometry (level and variability of weight, height, BMI) in two cohorts born around 1990 and 1974 and examined as young adults. METHODS: Descriptive results are presented for the complete cohorts. The final analysis age-matched the cohorts (mean, 18.8 years) and employed CDC z-scores to compare means and distributions of weight, height and BMI. RESULTS: Z-scores for weight, height and BMI were higher in later-born (1990) boys, while in girls weight and height increased over this period without resulting in increased BMI. At the same time, in boys the BMI variances increased, confirming a simultaneous emergence of more overweight and more underweight. In girls, the BMI variance did not increase significantly. Sensitivity analyses, excluding subjects not born in Sweden, confirmed increasing BMI trends in boys. CONCLUSION: This study documents that gender differences in the recent childhood obesity epidemic can also be observed in young Swedes as they enter adulthood. Comparing two cohorts of high school students born around 1974 or 1990, less favourable trends in weight status were seen in boys than in girls. Finally, secular increases in height, already observed earlier in the 20th century, continued in these more contemporary cohorts.

Exercise blood pressure and the risk of future hypertension.

The aim of this prospective cohort study was to identify which blood pressure measurement during exercise is the best predictor of future hypertension. Further we aimed to create a risk chart to facilitate the evaluation of blood pressure reaction during exercise testing. A number (n=1047) of exercise tests by bicycle ergometry, performed in 1996 and 1997 were analysed. In 2007-2008, 606 patients without hypertension at the time of the exercise test were sent a questionnaire aimed to identify current hypertension. The response rate was 58% (n=352). During the 10-12 years between exercise test and questionnaire, 23% developed hypertension. The strongest predictors of future hypertension were systolic blood pressure (SBP) before exercise (odds ratios (OR) 1.63 (1.31-2.01) for 10 mm Hg difference) in combination with the increase of SBP over time during exercise testing (OR 1.12 (1.01-1.24) steeper increase for every 1 mm Hg min(-1)). A high SBP before exercise and a steep rise in SBP over time represented a higher risk of developing hypertension. A risk chart based on SBP before exercise, increase of SBP over time and body mass index was created. SBP before exercise, maximal SBP during exercise and SBP at 100 W were significant single predictors of future hypertension and the prediction by maximal SBP was improved by adjusting for time/power at which SBP max was reached during exercise testing. Recovery ratio (maximal SBP/SBP 4 min after exercise) was not predictive of future hypertension.

Alcoholic beverages and incidence of dementia: 34-year follow-up of the prospective population study of women in Goteborg.

The objective of this study was to assess the association between different types of alcoholic beverages and 34-year incidence of dementia. Among a random sample of 1,462 women aged 38-60 years and living in Göteborg, Sweden, in 1968-1969, 164 cases of dementia were diagnosed by 2002. At baseline as well as in 1974-1975, 1980-1981, and 1992-1993, the frequency of alcohol intake, as well as other lifestyle and health factors, was recorded and related to dementia with Cox proportional hazard regression, by use of both baseline and updated covariates. Wine was protective for dementia (hazard ratio (HR) = 0.6, 95% confidence interval (CI): 0.4, 0.8) in the updated model, and the association was strongest among women who consumed wine only (HR = 0.3, 95% CI: 0.1, 0.8). After stratification by smoking, the protective association of wine was stronger among smokers. In contrast, consumption of spirits at baseline was associated with slightly increased risk of dementia (HR = 1.5, 95% CI: 1.0, 2.2). Results show that wine and spirits displayed opposing associations with dementia. Because a protective effect was not seen for the other beverages, at least part of the association for wine may be explained by components other than ethanol.

Energy distributions in multiple photon absorption experiments.

Photofragmentation experiments on molecules and clusters often involve multiple photon absorption. The distributions of the absorbed number of photons are frequently approximated by Poisson distributions. For realistic laser beam profiles, this approximation fails seriously due to the spatial variation of the mean number of absorbed photons across the laser beam. We calculate the distribution of absorbed energy for various laser and molecular-beam parameters. For a Gaussian laser beam, the spatially averaged distributions have a power-law behavior for low energy with a cutoff at an energy which is proportional to fluence. The power varies between -1 for an almost parallel laser beam and -5/2 for a divergent beam (on the scale of the molecular beam). We show that the experimental abundance spectra of fullerenes and small carbon clusters can be used to reconstruct the distribution of internal energy in the excited C60 molecule prior to fragmentation and find good agreement with the calculated curves.