Life course body mass index and risk and prognosis of amyotrophic lateral sclerosis: results from the ALS registry Swabia.

Weight loss appears as a strong predictor of survival of patients with amyotrophic lateral sclerosis, yet no data are currently available to describe the life course history of pre-diagnostic body mass index (BMI) in these patients. 393 ALS cases (mean age: 65.8 years, 57.3% men) and 791 controls matched by age and sex from a population-based case-control study of the ALS Registry Swabia were analyzed. Differences of BMI change in cases and controls over time were modeled using a multilevel additive model. In addition, survival in ALS cases by BMI change was modeled using an accelerated failure time model adjusted for prognostic factors. In ALS cases, BMI was consistently higher than in controls in the 20-70 years before the interview. Conditional logistic regression revealed an odds ratio of 1.05 (95% confidence interval (CI) 1.00-1.11, p = 0.041) per 1 kg/m2 higher BMI 35-45 years before interview. However, a sharp decrease was evident in the BMI of ALS cases about 10 years before disease onset. Moreover, weight loss was strongly associated with shorter survival in ALS patients. Illustrating this, patients with stable weight showed a median survival time of 22.1 (95%-CI 19.2-25.0) months, as compared to 13.4 (95%-CI 10.5-16.3) months for patients with weight loss of 2.5 kg/m2 over the last 3 months before the interview. Thus, alterations in body weight are present in ALS patients already decades before clinical manifestation of ALS, while weight loss precedes motor symptoms of several years and is associated with poor prognosis.

Epidemiologic research topics in Germany: a keyword network analysis of 2014 DGEpi conference presentations.

Knowledge of epidemiologic research topics as well as trends is useful for scientific societies, researchers and funding agencies. In recent years researchers recognized the usefulness of keyword network analysis for visualizing and analyzing scientific research topics. Therefore, we applied keyword network analysis to present an overview of current epidemiologic research topics in Germany. Accepted submissions to the 9th annual congress of the German Society for Epidemiology (DGEpi) in 2014 were used as data source. Submitters had to choose one of 19 subject areas, and were ask to provide a title, structured abstract, names of authors along with their affiliations, and a list of freely selectable keywords. Keywords had been provided for 262 (82 %) submissions, 1030 keywords in total. Overall the most common keywords were: "migration" (18 times), "prevention" (15 times), followed by "children", "cohort study", "physical activity", and "secondary data analysis" (11 times each). Some keywords showed a certain concentration under one specific subject area, e.g. "migration" with 8 of 18 in social epidemiology or "breast cancer" with 4 of 7 in cancer epidemiology. While others like "physical activity" were equally distributed over multiple subject areas (cardiovascular & metabolic diseases, ageing, methods, paediatrics, prevention & health service research). This keyword network analysis demonstrated the high diversity of epidemiologic research topics with a large number of distinct keywords as presented at the annual conference of the DGEpi.

Association of Serum Retinol-Binding Protein 4 Concentration With Risk for and Prognosis of Amyotrophic Lateral Sclerosis.

Importance: Knowledge about the metabolic states of patients with amyotrophic lateral sclerosis (ALS) may provide a therapeutic approach. Objective: To investigate the association between the onset and prognosis of ALS and serum retinol-binding protein 4 (RBP4) concentration as a biomarker for insulin resistance and vitamin A metabolism. Design, Setting, and Participants: Case-control design for risk factors of ALS; cohort design for prognostic factors within ALS cases. Between October 1, 2010, and June 30, 2014, a population-based case-control study with randomly selected controls was established based on the ALS Registry Swabia in southern Germany, with a target population of 8.4 million inhabitants. Response rates were 64.8% among the cases and 18.7% among the controls. The dates of analysis were April 2016 to May 2017. Main Outcomes and Measures: Serum samples were measured for RBP4. Information on covariates was assessed by an interview-based standardized questionnaire. Main outcomes and measures were adjusted odds ratios for risk of ALS associated with serum RBP4 concentration, as well as time to death associated with RBP4 concentration at baseline in ALS cases only. Conditional logistic regression was applied to calculate multivariable odds ratios for risk of ALS. Survival models were used in cases only to appraise their prognostic value. Results: Data from 289 patients with ALS (mean [SD] age, 65.7 [10.5] years; 172 [59.5%] male) and 504 controls (mean [SD] age, 66.3 [9.8] years; 299 [59.3%] male) were included in the case-control study. Compared with controls, ALS cases were characterized by lower body mass index, less educational attainment, smoking, light occupational work intensity, and self-reported diabetes. The median serum RBP4 concentration was lower in ALS cases than in controls (54.0 vs 59.5 mg/L). In the multivariable model, increasing RBP4 concentration was associated with reduced odds for ALS (top vs bottom quartile odds ratio, 0.36; 95% CI, 0.22-0.59; P for trend <.001), which persisted after further adjustment for renal function and for leptin and adiponectin. Among 279 ALS cases during a median follow-up of 14.5 months, 104 died (mean [SD] age, 68.9 [10.3] years; 56 [53.9%] male). In this ALS cohort, an inverse association was found between serum RBP4 concentration as a continuous measure and survival. Conclusions and Relevance: RBP4 was inversely related to risk for and prognosis of ALS, suggesting that vitamin A metabolism or impaired insulin signaling could be involved. Further research, including a prospective design and other biological markers, is necessary to clarify the role of insulin resistance in the pathogenesis of ALS.