Ylva Trolle Lagerros

Effect of a very low energy diet on moderate and severe obstructive sleep apnoea in obese men: a randomised controlled trial.

Objective To assess the effect of weight loss induced by a very low energy diet on moderate and severe obstructive sleep apnoea in obese men. Design Single centre, two arm, parallel, randomised, controlled, open label trial. Blocked randomisation procedure used for treatment allocation. Setting Outpatient obesity clinic in a university hospital in Stockholm, Sweden. Participants 63 obese men (body mass index 30-40, age 30-65 years) with moderate to severe obstructive sleep apnoea (apnoea-hypopnoea index (AHI) ≥15), treated with continuous positive airway pressure. Interventions The intervention group received a liquid very low energy diet (2.3 MJ/day) for seven weeks to promote weight loss, followed by two weeks of gradual introduction of normal food, reaching 6.3 MJ/day at week 9. The control group adhered to their usual diet during the nine weeks of follow-up. Main outcome measure AHI, the major disease severity index for obstructive sleep apnoea. Data from all randomised patients were included in an intention to treat analysis (baseline carried forward for missing data). Results Of the 63 eligible patients, 30 were randomised to intervention and 33 to control. Two patients in the control group were dissatisfied with allocation and immediately discontinued. All other patients completed the trial. Both groups had a mean AHI of 37 events/h (SD 15) at baseline. At week 9, the intervention group’s mean body weight was 20 kg (95% confidence interval 18 to 21) lower than that of the control group, while its mean AHI was 23 events/h (15 to 30) lower. In the intervention group, five of 30 (17%) were disease free after the energy restricted diet (AHI <5), with 15 of 30 (50%) having mild disease (AHI 5-14.9), whereas the AHI of all patients in the control group except one remained at 15 or higher. In a subgroup analysis of the intervention group, baseline AHI significantly modified the effectiveness of treatment, with a greater improvement in AHI in patients with severe obstructive sleep apnoea (AHI >30) at baseline compared with those with moderate (AHI 15-30) sleep apnoea (AHI −38 v −12, P<0.001), despite similar weight loss (−19.2 v −18.2 kg, P=0.55). Conclusion Treatment with a low energy diet improved obstructive sleep apnoea in obese men, with the greatest effect in patients with severe disease. Long term treatment studies are needed to validate weight loss as a primary treatment strategy for obstructive sleep apnoea. Trial registration Current Controlled Trials ISRCTN70090382.

Web-based and mailed questionnaires : A comparison of response rates and compliance

Background: We assessed response rates and compliance for a printed questionnaire and a Web questionnaire in a Swedish population-based study and explored the influence of adding personalized feedback to the Web questionnaire. Methods: We assigned 875 subjects to 1 of 3 groups: printed questionnaire, plain Web questionnaire, or Web questionnaire with personalized feedback. The questionnaire had 2 parts, first a general section and then a dietary section. Results: The response rate for the general section was 64% for the printed questionnaire, compared with 50% for the Web questionnaire with feedback. For the dietary questionnaire, the rates were reversed, resulting in a total response rate for the dietary questionnaire that did not differ between printed and web questionnaire with feedback. Conclusions: Interactivity in the Web questionnaire increased compliance in completion of the second section of the questionnaire. Web questionnaires can be useful for research purposes in settings in which Internet access is high.

Outcomes of Pregnancy after Bariatric Surgery

BACKGROUND Maternal obesity is associated with increased risks of gestational diabetes, large-for-gestational-age infants, preterm birth, congenital malformations, and stillbirth. The risks of these outcomes among women who have undergone bariatric surgery are unclear. METHODS We identified 627,693 singleton pregnancies in the Swedish Medical Birth Register from 2006 through 2011, of which 670 occurred in women who had previously undergone bariatric surgery and for whom presurgery weight was documented. For each pregnancy after bariatric surgery, up to five control pregnancies were matched for the mothers presurgery body-mass index (BMI; we used early-pregnancy BMI in the controls), age, parity, smoking history, educational level, and delivery year. We assessed the risks of gestational diabetes, large-for-gestational-age and small-for-gestational-age infants, preterm birth, stillbirth, neonatal death, and major congenital malformations. RESULTS Pregnancies after bariatric surgery, as compared with matched control pregnancies, were associated with lower risks of gestational diabetes (1.9% vs. 6.8%; odds ratio, 0.25; 95% confidence interval [CI], 0.13 to 0.47; P<0.001) and large-for-gestational-age infants (8.6% vs. 22.4%; odds ratio, 0.33; 95% CI, 0.24 to 0.44; P<0.001). In contrast, they were associated with a higher risk of small-for-gestational-age infants (15.6% vs. 7.6%; odds ratio, 2.20; 95% CI, 1.64 to 2.95; P<0.001) and shorter gestation (273.0 vs. 277.5 days; mean difference -4.5 days; 95% CI, -2.9 to -6.0; P<0.001), although the risk of preterm birth was not significantly different (10.0% vs. 7.5%; odds ratio, 1.28; 95% CI, 0.92 to 1.78; P=0.15). The risk of stillbirth or neonatal death was 1.7% versus 0.7% (odds ratio, 2.39; 95% CI, 0.98 to 5.85; P=0.06). There was no significant between-group difference in the frequency of congenital malformations. CONCLUSIONS Bariatric surgery was associated with reduced risks of gestational diabetes and excessive fetal growth, shorter gestation, an increased risk of small-for-gestational-age infants, and possibly increased mortality. (Funded by the Swedish Research Council and others.).

Assessment of physical activity and energy expenditure in epidemiological research of chronic diseases

Physical inactivity has emerged as an important risk factor for a number of diseases, but the typically crude exposure assessments in epidemiological studies, with entailing variation in measurement accuracy, may be a source of heterogeneity contributing to inconsistent results among studies. Consequently, the choice of method for the assessment of physical activity in epidemiological studies is important. Good methods increase our chances of avoiding misclassification and may enhance our understanding of the association between physical activity and health. Since physical activity is also a potential confounder of other lifestyle-health relationships, good methods may enhance our ability to control for confounding. But despite a steadily increasing selection of methods to choose from, no method is suitable for every situation and every population. Although the questionnaire is the most widely used method in epidemiological studies, and laboratory methods are mainly used for validation purposes, improved technology may change our ways of assessing physical activity in the future. This paper describes different methods to measure physical activity and energy expenditure from the epidemiological perspective, and attempts to address the concepts related to the measurement of physical activity.

High birth weight and obesity—a vicious circle across generations

OBJECTIVES:Rates of high birth weight infants, overweight and obese children and adults are increasing. The associations between birth weight and adult weight may have consequences for the obesity epidemic across generations. We examined the association between mothers’ birth weight for gestational age and adult body mass index (BMI) and these factors’ joint effect on risk of having a large-for-gestational-age (LGA) offspring (>+2 s.d. above the mean).DESIGN:A cohort of 162 676 mothers and their first-born offspring with birth information recorded on mothers and offspring in the nation-wide Swedish Medical Birth Register 1973–2006.RESULTS:Compared with mothers with appropriate birth weight for gestational age (AGA; −1 to +1 s.d.), mothers born LGA had increased risks of overweight (BMI 25.0–29.9; odds ratio (OR), 1.50; 95% CI 1.39–1.61), obesity class I (BMI 30.0–34.9; OR 1.77; 95% CI 1.59–1.98), obesity class II (BMI 35.0–39.9; OR 2.77; 95% CI 2.37–3.24) and obesity class III (BMI ⩾40.0; OR 2.04; 95% CI 1.49–2.80). In each stratum of mothers birth weight for gestational age, risk of having an LGA offspring increased with mothers BMI. The risk of an LGA offspring was highest among women with a high (⩾30) BMI who also had a high birth weight for gestational age (>+1 s.d.). In these groups, the ORs for LGA offspring ranged from 5 to 14 when compared with mothers born AGA with normal BMI (⩽24.9). However, the strongest increase in risk by BMI was seen among mothers born SGA: the OR of having an LGA offspring was 13 times as high among SGA mothers with BMI ⩾35.0 compared with the OR among SGA mothers with normal BMI (ORs=4.61 and 0.35, respectively).CONCLUSIONS:Prenatal conditions are important for the obesity epidemic. Prevention of LGA births may contribute to curtail the intergenerational vicious cycle of obesity.

Longer term effects of very low energy diet on obstructive sleep apnoea in cohort derived from randomised controlled trial: prospective observational follow-up study

Objective To determine whether initial improvements in obstructive sleep apnoea after a very low energy diet were maintained after one year in patients with moderate to severe obstructive sleep apnoea. Design Single centre, prospective observational follow-up study. Setting Outpatient obesity clinic in a university hospital in Stockholm, Sweden. Participants 63 men aged 30-65 with body mass index (BMI) 30-40 and moderate to severe obstructive sleep apnoea defined as an apnoea-hypopnoea index ≥15 (events/hour), all treated with continuous positive airway pressure. Intervention A one year weight loss programme, consisting of an initial very low energy diet for nine weeks (seven weeks of 2.3 MJ/day and two weeks of gradual introduction of normal food) followed by a weight loss maintenance programme. Main outcome measure Apnoea-hypopnoea index, the main index for severity of obstructive sleep apnoea. Data from all patients were analysed (baseline carried forward for missing data). Results Of 63 eligible patients, 58 completed the very low energy diet period and started the weight maintenance programme and 44 completed the full programme; 49 had complete measurements at one year. At baseline the mean apnoea-hypopnoea index was 36 events/hour. After the very low energy diet period, apnoea-hypopnoea index was improved by −21 events/hour (95% confidence interval −17 to −25) and weight by −18 kg (−16 to −19; both P<0.001). After one year the apnoea-hypopnoea index had improved by −17 events/hour (−13 to −21) and body weight by −12 kg (−10 to −14) compared with baseline (both P<0.001). Patients with severe obstructive sleep apnoea at baseline had greater improvements in apnoea-hypopnoea index (−25 events/hour) compared with patients with moderate disease (−7 events/hour, P<0.001). At one year, 30/63 (48%, 95% confidence interval 35% to 60%) no longer required continuous positive airway pressure and 6/63 (10%, 2% to 17%) had total remission of obstructive sleep apnoea (apnoea-hypopnoea index <5 events/hour). There was a dose-response association between weight loss and apnoea-hypopnoea index at follow-up (β=0.50 events/kg, 0.11 to 0.88; P=0.013). Conclusion Initial improvements in obstructive sleep apnoea after treatment with a very low energy diet can be maintained after one year in obese men with moderate to severe disease. Those who lose the most weight or have severe sleep apnoea at baseline benefit most. Trial registration Current Controlled Trials 70090382.

Physical activity in adolescence and young adulthood and breast cancer risk: a quantitative review.

Physical activity habits are potentially modifiable and could therefore be targeted in a primary prevention strategy against breast cancer, provided there is causality and a sufficiently strong relationship. Our objective of this quantitative review was to provide a summary estimate of the association of moderate/vigorous recreational physical activity during adolescence/young adulthood with breast cancer risk, and to determine whether a dose-response relationship exists. Data sources included studies in humans relating physical activity to breast cancer risk, published between January 1966 and October 2002, identified on Medline, the Web of Science, from reference lists and related reviews. The main characteristics of each study, the point estimates of relative risk (RR) and confidence intervals (CI) were extracted from 19 case-control and four cohort studies. Comparing the highest to the lowest category of physical activity, the summary RR from the random effects model was 0.81 (95% CI 0.73–0.89). This almost 20% risk reduction proved to be fairly consistent, despite variation in populations and methods. Each one-hour increase of recreational physical activity/week during adolescence was associated with a 3% (95% CI 0–6%) risk reduction. Physical activity in 12–24-year-old females significantly reduces risk of breast cancer. Heterogeneity may be explained by different methods to measure activity.

Perinatal outcomes after bariatric surgery: nationwide population based matched cohort study

Objective To compare perinatal outcomes in births of women with versus without a history of bariatric surgery. Design Population based matched cohort study. Setting Swedish national health service. Participants 1 742 702 singleton births identified in the Swedish medical birth register between 1992 and 2009. For each birth to a mother with a history of bariatric surgery (n=2562), up to five control births were matched by maternal age, parity, early pregnancy body mass index, early pregnancy smoking status, educational level, and year of delivery. Secondary control cohorts, including women eligible for bariatric surgery (body mass index ≥35 or ≥40), were matched for the same factors except body mass index. History of maternal bariatric surgery was ascertained through the Swedish national patient register from 1980 to 2009. Main outcome measures Preterm birth (<37 weeks), small for gestational age birth, large for gestational age birth, stillbirth (≥28 weeks), and neonatal death (0-27 days). Results Post-surgery births were more often preterm than in matched controls (9.7% (243/2511) v 6.1% (750/12 379); odds ratio 1.7, 95% confidence interval 1.4 to 2.0; P<0.001). Body mass index seemed to be an effect modifier (P=0.01), and the increased risk of preterm birth was only observed in women with a body mass index <35. A history of bariatric surgery was associated with increased risks of both spontaneous (5.2% (130/2511) v 3.6% (441/12 379); odds ratio 1.5, 1.2 to 1.9; P<0.001) and medically indicated preterm birth (4.5% (113/2511) v 2.5% (309/12 379); odds ratio 1.8, 1.4 to 2.3; P<0.001). A history of bariatric surgery was also associated with an increased risk of a small for gestational age birth (5.2% (131/2507) v 3.0% (369/12 338); odds ratio 2.0, 1.5 to 2.5; P<0.001) and lower risk of a large for gestational age birth (4.2% (105/2507) v 7.3% (895/12 338); odds ratio 0.6, 0.4 to 0.7; P<0.001). No differences were detected for stillbirth or neonatal death. The increased risks for preterm and small for gestational age birth, as well as the decreased risk for large for gestational age birth, remained when post-surgery births were compared with births of women eligible for bariatric surgery. Conclusion Women with a history of bariatric surgery were at increased risk of preterm and small for gestational age births and should be regarded as a risk group during pregnancy.

Measures of Physical Activity Using Cell Phones: Validation Using Criterion Methods

Background Physical activity is associated with reduced risks of many chronic diseases. Data collected on physical activity in large epidemiological studies is often based on paper questionnaires. The validity of these questionnaires is debated, and more effective methods are needed. Objective This study evaluates repeated measures of physical activity level (PAL) and the feasibility of using a Java-based questionnaire downloaded onto cell phones for collection of such data. The data obtained were compared with reference estimates based on the doubly labeled water method and indirect calorimetry (PALref). Method Using a Java-based cell phone application, 22 women reported their physical activity based on two short questions answered daily over a 14-day period (PALcell). Results were compared with reference data obtained from the doubly labeled water method and indirect calorimetry (PALref). Results were also compared against physical activity levels assessed by two regular paper questionnaires completed by women at the end of the 14-day period (PALquest1 and PALquest2). PALcell, PALquest1, and PALquest2 were compared with PALref using the Bland and Altman procedure. Results The mean difference between PALcell and PALref was small (0.014) with narrow limits of agreement (2SD = 0.30). Compared with PALref, the mean difference was also small for PALquest1 and PALquest2 (0.004 and 0.07, respectively); however, the limits of agreement were wider (PALquest1, 2SD = 0.50 and PALquest2, 2SD = 0.90). The test for trend was statistically significant for PALquest1 (slope of regression line = 0.79, P = .04) as well as for PALquest2 (slope of regression line = 1.58, P < .001) when compared with PALref. Conclusion A Java-based physical activity questionnaire administered daily using cell phones produced PAL estimates that agreed well with PAL reference values. Furthermore, the limits of agreement between PAL obtained using cell phones, and reference values were narrower than for corresponding estimates obtained using paper questionnaires. Java-based questionnaires downloaded onto cell phones may be a feasible and cost-effective method of data collection for large-scale prospective studies of physical activity.

Physical activity and risk of Parkinson’s disease in the Swedish National March Cohort

Physical exercise has been associated with neuroprotective effects in the nigrostriatal dopaminergic system. To examine the impact of physical activity on Parkinsons disease risk prospectively, we followed 43 368 individuals who provided extensive information on physical activity at baseline. We estimated hazard ratios with 95% confidence intervals using Cox proportional hazards regression. During an average of 12.6 years of follow-up, 286 incident Parkinsons disease cases were identified. In males, there was an inverse association with Parkinsons disease for total physical activity (hazard ratio 0.55, 95% confidence interval 0.35-0.87 for medium versus low level), for sum of household, commuting and leisure time exercise (hazard ratio 0.53, 95% confidence interval 0.33-0.85 for high versus low level), and for household and commuting physical activity specifically (hazard ratio 0.50, 95% confidence interval 0.31-0.81 for >6 versus <2 h per week). No association was observed for leisure time exercise or occupational physical activity with Parkinsons disease, among either males or females. Meta-analysis of the present study and five previous prospective studies showed a pooled hazard ratio of 0.66 (95% confidence interval 0.57-0.78) for highest versus lowest physical activity level. Our results indicate that a medium level of physical activity lowers Parkinsons disease risk.