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Objective: This study examines the effects of telephone and mail interview methods on the measurement of health-related quality of life., Study Design and Setting: One thousand six hundred ninety individuals aged 25-66 were interviewed randomly either by telephone or by mail. Health-related quality of life was assessed with the German SF-8., Results: Although respondents in the telephone survey were more willing to participate (77.4% vs. 47.5%) the difference in the accessibility of publicly available address and telephone records meant that overall more people were interviewed by mail than by telephone (53.2% vs. 46.8%). No differences occurred in terms of the sociodemographic makeup. Telephone respondents gave a more positive account of the mental dimension of their health-related quality of life; whereas mail interviews led to a better rating of the respondents' physical well-being. Gender-specific analyses indicate a slight discrepancy in the influence of the method of interviewing on men and women. Further differences were identified concerning the variance in the existence of ceiling and floor effects and the correlation between items., Conclusion: Found differences are small but at least to be valued as relevant in certain settings. Therefore, we approve the use and development of factors of amendment.

Within a comprehensive comparison of telephone and postal survey methods the SF-8 was applied to assess adult's health-related quality of life. The 1690 subjects were randomly assigned to a telephone survey and a postal survey. Comparisons across the different modes of administration addressed the response rates, central tendency, deviation, ceiling and floor effects observed in the SF-8 scores as well as the inter-item correlation. The importance of age and gender as moderating factors was investigated. Results indicate no or small statistically significant differences in the responses to the SF-8 depending on the actual mode of administration and the health aspect questioned. It was concluded that further investigations should focus on the exact nature of these deviations and try to generate correction factors.

Unlabelled: The DXA-technique is a well established method to study bone mineral density (BMD). Until now there are no reliable reference data based on the male population of Germany., Question: Are the data base, given by the manufacturer transferable to the male population in Germany?, Methods: So a cross sectional study based on 715 healthy males with German ethnic background (age 20-89) was carried out. Comparison was made to the ap spine reference data of northern Europe., Results: The peak bone mass was 1,26 +/- 0,17 g/cm2 at the age of 20-24 years. After that the BMD decreases to the sixth decade (1,09 +/- 0,18 g/cm2), further on there is an increase to 1,18 +/- 0,21 g/cm2 in the ninth decade., Conclusion: Looking at a comparable Swedish study there are no significant differences, looking at a Finnish study there are statistically significant differences in the sixth decade (t = 3,246) and seventh decade (t = 2,413). The results of our study complete the data base until now, but one should be careful to transfer the data base provided by the manufacturer.