Biomedical subjects

D Böhning

Publications and source records attributed to D Böhning.

25 records · Page 2Linked to original sources

PubMed1990

Relationship of the morbidity of under-fives to anthropometric measurements and community health intervention.

In a 3-year prospective morbidity study in seven villages of northeast Thailand the health of preschool children was assessed every alternate week by questioning the mothers. The nutritional status was determined by weight-for-age, weight-for-height and height-for-age every third month. In four villages active measures were undertaken to improve the health and nutritional status of the children. A child had an average of 2.5 illness episodes and was ill 14.1 days per year. More than 80% of all illness episodes could be accounted to ill-defined infections such as fever and cough with only 5.2% accountable to diarrhoea. A marked decline in the rate of illness episodes was observed in communities where cooperation was good. Weight-for-height is a better indicator for determining children at risk of falling ill than weight-for-age and height-for-age. The duration of illness episodes was not related to the nutritional status.

Body Height↗

PubMed1988

Confidence interval estimation of a rate and the choice of sample size.

The problem of estimating a rate or proportion is considered. Four methods for constructing an approximate confidence interval are discussed and compared via a simulation study. The most accurate method is found. Also, for each method a sharp upper bound (dependent only on the sample size) is given for the length of the confidence interval. By choosing an appropriate sample size this bound enables the practitioner to achieve a prespecified maximum length for the confidence interval without knowing the population rate. The striking result is that the most accurate method has the smallest bound, thus requiring the least sample units.

Computer Simulation↗

PubMed1983

Human serum proteins indicative for the nutritional status and serum proteinase inhibitors in uncomplicated falciparum malaria.

The serum proteins supposed to be indicative of the nutritional status, albumin, prealbumin and transferrin, as well as the serum proteinase inhibitors alpha 1-protease inhibitor (alpha 1-antichymotrypsin (Ach) and alpha 2-macroglobulin (alpha 2M) were measured in 14 Thai males suffering from uncomplicated falciparum malaria on the day of admission and after treatment with mefloquin on the 2nd, 28th and 63rd day. The same serum proteins had been determined from 31 healthy Thai males. Upon admission albumin and prealbumin concentrations had been lower and Ach higher in malaria patients compared with healthy Thai males. A significantly higher alpha 1 PI value was observed on the day of admission compared with the 28th day of the malaria patients. Only on the day of admission and only for the patients was a statistically significant negative linear regression found for albumin and prealbumin with Ach and a positive correlation for prealbumin with alpha 2 M as well as for albumin and transferrin correlated with alpha 1 PI. In well-nourished malaria patients the synthesis of the "acute phase reactants", alpha 1 PI and Ach, might be enhanced and in a reverse relationship the synthesis of albumin, pre-albumin and transferrin depressed.

Animals↗

PubMedDate not supplied

Covariate adjusted mixture models and disease mapping with the program DismapWin.

The analysis and recognition of disease clustering in space and its representation on a map is an important problem in epidemiology. An approach using mixture models to identify spatial heterogeneity in disease risk and map construction within an empirical Bayes framework is described. Once heterogeneity is detected, the question arises as how explanatory variables could be included in the model. A mixed Poisson regression approach to include covariates is presented. The methods are illustrated using data for tuberculosis from Berlin in 1991.

Algorithms↗

PubMedDate not supplied

Space-time mixture modelling of public health data.

This paper aims to enlarge the usual scope of disease mapping by means of dynamic mixtures (DMDM) in case a time component is involved in the data. A special mixture model is suggested which looks for space-time components (clusters) simultaneously. The idea is illustrated using data on female lung cancer from the East German cancer registry for 1960-1989. The conventional mixed Poisson regression model is used as a third model for comparison. The models are discussed in terms of their benefits, difficulties and ease in interpretation, as well as their statistical meaning. Some ideas on evaluation of these models are also included.

Algorithms↗

PubMedDate not supplied

Non-parametric maximum likelihood estimators for disease mapping.

A Non-Parametric Maximum Likelihood approach to the estimation of relative risks in the context of disease mapping is discussed and a NPML approximation to conditional autoregressive models is proposed. NPML estimates have been compared to other proposed solutions (Maximum Likelihood via Monte Carlo Scoring, Hierarchical Bayesian models) using real examples. Overall, the NPML autoregressive estimates (with weighted term) were closer to the Bayesian estimates. The exchangeable NPML model ranked immediately after, even if it implied a greater shrinkage, while the truncated auto-Poisson showed inadequate for disease mapping. The coefficients of the autoregressive term for the different mixtures have clear interpretations: in the breast cancer example, the larger cities in the region showed high rates and very low correlation with the neighbouring areas, while the less populated rural areas with low rates were strongly positively correlated each other. This pattern is expected since breast cancer is strongly correlated with parity and age at first birth, and the female population of the rural areas experienced a decline in fertility much later than those living in the larger cities. The leukemia example highlighted the failure of the Poisson-Gamma model and other general overdispersion tests to detect high risk areas under specific conditions. The NPML approach in Aitkin is very general, simple and flexible. However the user should be warned against the possibility of local maxima and the difficulty in detecting the optimal number of components. Special software (such as CAMAN or DismapWin) had been developed and should be recommended mainly to not experienced users.

Algorithms↗

PubMedDate not supplied

Traffic accident mapping in Bangkok metropolis: a case study.

Results from an analysis of traffic accidents from a study of the police records of four police stations in the Bangkok metropolis are presented. The main emphasis in this study was put on the development of a measure for traffic accident density. The traffic flow was estimated at the various study locations by trained experts. By relating the frequency of traffic accidents found in the police records to the independently estimated traffic flow, a measure for traffic accident occurrence, the traffic accident density, was constructed and estimated for the 47 areas in four study locations. The spatial risk structure was estimated and three risk groups were identified. Each area was classified into its associated risk group, and traffic accident maps for the four study locations in the Bangkok metropolis are provided here. The implication for prevention strategies is discussed.

Accidents, Traffic↗