A lateral cephalometry study of patients with neurofibromatosis type 1.

Purpose: Neurofibromatosis type 1 (NF1) is an autosomal dominant transmitted tumour suppressor syndrome and also a bone disease. Osseous dysplasia affecting the craniofacial region is characteristic of NF1. The aim of this study was to analyse the lateral cephalograms of NF1 patients in comparison to individuals who were not affected by this condition in order to describe the skeletal phenotype of NF1 in more detail.

Effect of occupational air pollutants on various histological types of lung cancer: a population based case-control study.

A population based case-control study was performed in Cracow, Poland, to determine the effect of occupational air pollutants on various histological types of lung cancer. Male cases and controls were identified from the Cracow Death Register. Information was obtained by mailed questionnaire from next of kin on smoking, occupational branch, occupational exposures, and other pertinent variables.

Follow-up study among model and pattern makers in an automobile company in the Federal Republic of Germany.

The follow-up of a cohort of 528 model makers and a control group of 2273 tool makers shows an unusual pattern of mortality in the model makers' cohort. In contrast to the usual ranking, malignant neoplasms are the most frequent group of cause of death followed by diseases of the cardiovascular system. The rate ratio (RR) for malignant tumors is significantly increased among model makers compared with tool makers RR = 1.

Power calculation for cohort studies with improved estimation of expected numbers of deaths.

This paper focuses on improving the accuracy of sample size calculations for cohort studies by careful calculation of the expected number of deaths in the population, taking into account either prior information or realistic assumptions about variables which may affect the mortality or incidence. Sometimes small changes in the assumptions can dramatically alter the expected numbers and may necessitate modifications in the design of the study. Possible modification include extension of the follow-up time, and recognition that the real strength of the study may lie in the potential for pooling several similar studies.

Dietary risk factors in intestinal and diffuse types of stomach cancer: a multicenter case-control study in Poland.

A hospital-based, multicenter, case-control study has been performed in Poland covering 741 incident stomach-cancer cases (520 males and 221 females) and the same number of controls. All stomach-cancer diagnoses were evaluated for histologic type according to the Lauren criteria. Fifty-one percent were of the intestinal type, 35 percent of the diffuse type, and 8.

Alternative parameterization of polychotomous models: theory and application to matched case-control studies.

A method is proposed for transforming a class of models having an outcome variable with more than two levels into an equivalent binary model. The polychotomous logistic model is used to demonstrate the method. The equivalency to a simple logistic regression model after some data transformation (augmentation) is shown.

Epidemiological research in stomach cancer: progress over the last ten years.

In this paper the progress of epidemiological research in stomach cancer during 1980-1990 is reviewed in respect to regional variation, etiology, and formation of carcinogens. The evaluation of 4 cohort and 16 case-control studies revealed a consistently inverse relationship of stomach cancer risk with raw vegetables, fruit, and wholemeal bread consumption and with vitamin C and carotene intake. Milk, cooked vegetables and vitamins A and E were not consistently found to be related to stomach cancer risk.

Biological assays for irritant, tumor-initiating and -promoting activities. III. Computer-assisted management and validation of biodata generated by standardized initiation/promotion protocols in skin of mice.

The initiation/promotion standard protocol 28 (protocol 28), developed and used previously as an experimental model to verify the cancerogenic process of initiation/promotion in mouse skin, was revised in three aspects: (a) statistically it was shown sufficient to use, per promoter dose group, 16 colony-outbred female NMRI mice: (b) by weekly individual records of tumor response (and health status) of each mouse in a dose group, cumulative tumor incidences (and mean and extreme body weights) are determined; from these data the collective records (tumor response, health status), the only data accessible from protocol 28, may be generated in addition; (c) the details of dose groups and all data on tumor response and health status are processed by computer using the program package PAPILLOM. The latter was developed specifically for this purpose, is written in the programming language APL and designed for easy handling by staff of animal laboratories. The program package calculates, from the individual records per promoter dose group, cumulative tumor incidences (and survival data) with confidence limits for any one exposure time, and the package may be linked to programs for statistical validations.

Epidemiological study of precursor lesions of oesophageal cancer among young persons in Huixian, China.

A total of 538 subjects (354 males, 184 females) were investigated in a high-risk area for oesophageal cancer in China to provide large-scale data on the prevalence of chronic oesophagitis among persons below 25 years of age. The survey included an oesophagoscopy with guided biopsies and cytology, a physical examination, an interview and collection of a 10-ml blood sample and overnight urine. Histologically confirmed oesophagitis was found in 43.

Adjusting for misselection using subsampling in epidemiological studies.

In epidemiological research it is sometimes necessary to conduct a case-control study in a part of the population which is not exposed to certain risk factors. Such a study design may be useful to investigate the risk related to a weak carcinogen in presence of other strong risk factors. It may happen that some individuals are wrongly included in the study group due to misreporting of the true exposure status.

Occupational risk factors for brain tumors: results from a population-based case-control study in Germany.

In a population-based case-control study in the Rhein-Neckar-Odenwald area (containing 1.3 million inhabitants) of the Federal Republic of Germany (FRG), risk factors were assessed for brain tumor development in 226 cases with primary brain tumors (ICD-9 191, 192.1, 192.

An epidemiological study of precursor lesions of esophageal cancer among young persons in a high-risk population in Huixian, China.

The occurrence of chronic esophagitis, considered a precursor condition for esophageal cancer, among persons 15 to 26 yr of age and risk factors for the disease were investigated in Huixian, Henan Province, a high-risk area for esophageal cancer in the People's Republic of China. The 538 study subjects underwent an esophagoscopy with guided biopsies and cytology, a physical examination, an interview with a questionnaire including known and suspected risk factors for esophageal lesions, and collection of a 10-ml blood sample and overnight urine. One-third of the subjects was selected from households with a case of esophageal cancer in the past 6 yr and two-thirds came from control households.

Statistical aspects of experimental studies with complex mixtures.

Some formal concepts are introduced relating to the statistical design and analysis of experiments with complex mixtures. Aspects relating to the chemical analysis of complex mixtures, identification of their major components, continuous monitoring of samples or related issues are not addressed. As a surrogate for experimental studies in general, the discussion is oriented towards the situation of long-term animal experiments.

Precursor lesions of oesophageal cancer in young people in a high-risk population in China.

Young people (15-26 years) were selected from households in a population in China at high risk of oesophageal cancer on the basis of whether a case of oesophageal cancer had (166 participants) or had not (372 participants) occurred in a first-degree relative. In an endoscopic survey 43.5% of the male subjects and 35.

Cumulative damage models of additional exposures and host factors.

Cumulative damage models represent a mathematically accurate conceptualized approach for the consideration of various problems of descriptive and analytical epidemiology. This study demonstrates the application of these models to situations where additional exposures, e.g.

Results from a comparative dietary assessment in Europe: II. Feasibility of pooling individual-based dietary data between countries.

Dietary investigations in four central European survey populations carried out in the German Democratic Republic, Poland and Denmark between 1982 and 1984 using different methodologies were analysed in order to assess the possibilities of characterizing the dietary habits of individual survey participants in a comparable fashion. This was done with the view of assessing the feasibility of a pooled cancer cohort study. For this purpose a method has been devised to combine dietary information derived by food frequency questionnaires and quantitative recording methods into a quantitative characterization of individuals' habits.

Results from a comparative dietary assessment in Europe: I. Comparison of dietary information derived from concurrently applied frequency questionnaires and quantitative measurement instruments.

Data from four central European dietary investigations carried out between 1982 and 1984 in the German Democratic Republic, Poland and the Federal Republic of Germany applying both a food frequency questionnaire (FFQ) and a quantitative recording instrument (24-h recall, 3-d record or 10- to 14-d record) were analysed to compare frequency of food consumption as reported by the FFQ with the corresponding information as derived from the quantitative instrument. The actual intake was found to be overestimated by the FFQ for categories of frequent consumption and underestimated for categories of rare consumption. Categories for which both instruments yielded similar estimates of frequency were found to vary between food items and to depend on the overall frequency of consumption of an item.

Time trends in cancer mortality in the Federal Republic of Germany: progress against cancer?

In accordance with a previous analysis of US cancer mortality, this report also indicates that cancer mortality in the FRG over the last 3 decades (1952-1985) has not shown any decline commencing in a given period and prevailing in all age groups. If present, such effects could have been interpreted as a manifestation of improvements associated with cancer treatment. The absence of such an effect, derived by using data up to 1985 and age-specific mortality rates, supports the view expressed in the US analysis that improvements in cancer treatment are unlikely to have an impact on overall cancer mortality statistics and that efforts toward prevention may be more rewarding.

Lung cancer, smoking, and employment in foundries.

A case-referent study on lung cancer was conducted in Cracow, Poland. Men dying of lung cancer within a 6-year period (1980-1985) formed the case group. The reference series was selected from death registers and was frequency-matched with the cases by sex and age.

Blood, retinol and zinc riboflavin status in relation to precancerous lesions of the esophagus: findings from a vitamin intervention trial in the People's Republic of China.

Data from a double-blind intervention trial in China are reanalyzed to explore auxiliary information. The trial had shown that in a high-risk area for esophageal cancer the dietary supplementation of apparently healthy individuals with a combination of retinol, riboflavin, and zinc did not lead to a different prevalence of precancerous lesions of the esophagus among those receiving the active treatment compared to a placebo group. However, improvement of blood retinol and zinc levels were also observed in the placebo group.

Occupation and risk of cancer of the lower urinary tract among men. A case-control study.

Data from a hospital-based matched case-control study with 531 male pairs were analyzed for risks of cancer of the lower urinary tract associated with previous employment and particular occupational exposures. Statistically significant odds ratios were obtained for ever-employment as mining workers (2.0), turners (2.

Mortality among German vegetarians: first results after five years of follow-up.

A prospective study of vegetarians recruited from all regions of the Federal Republic of Germany, including West Berlin, was started in 1978 after a preparatory phase of two years in which the cohort was established. The mortality of the 1,904 study participants was evaluated after a follow-up of five years, comparing observed deaths with expected rates based on the national mortality statistics. Of the 858 men and 1,046 women, 89% had followed their diet for at least five years at study entry, the majority of them as strict vegetarians (1,163).

An estimate of the proportion of colo-rectal and stomach cancers which might be prevented by certain changes in dietary habits.

The colo-rectum and stomach are the 2 sites for which the role of diet in the etiology of cancer is most heavily implicated. Quantitative estimates as to the proportion of cancer deaths attributable to diet vary considerably. This may be partially due to the application of the concept of population attributable risk which has proved a useful yardstick in estimating the public health impact of completely removing an exposure factor under study.