Impact of neighbourhood on physical activity (PA) is under-investigated in European adolescents, ... more Impact of neighbourhood on physical activity (PA) is under-investigated in European adolescents, and few studies have used objective data on both exposures and outcomes. Therefore we investigated the association between objectively measured neighbourhood characteristics and PA in 15-year-old German adolescents. Study populations comprised of 688 adolescents residing in the urban Munich area and 504 from the rural Wesel area from the GINIplus and LISAplus birth cohorts. Neighbourhood was defined as a circular 500-m buffer around the residence. Greenness was calculated 1) as the mean Normalized Difference Vegetation Index (NDVI), and 2) as percent tree cover. Neighbourhood green spaces and sport and leisure facilities were defined as present or absent in a neighbourhood (data only available for Munich). Data on PA were collected from one-week triaxial accelerometry (hip-worn ActiGraph GT3X). Minutes of PA were classified into moderate-to-vigorous (MVPA), light and sedentary using Romanzini's et al. triaxial cutoffs, and averaged over the recording period. Activity diaries were used for differentiation between school and leisure (total minus school) PA. Area-specific associations were assessed by adjusted negative binomial regressions. In the Wesel area, residing in a neighbourhood with higher NDVI was associated with 9% more leisure MVPA among females and with 8% more leisure MVPA in rural dwellers. In the Munich area, residing in a neighbourhood with sport facilities was associated with 9% more leisure MVPA. The latter association was only significant in urban dwellers while neighbourhood leisure facilities increased MVPA in rural dwellers. Estimates were very similar when total MVPA was considered rather than solely leisure. There is indication that neighbourhood features could be associated with MVPA in German adolescents. However, different features seem to be important across sexes and in rural/urban settings, which need to be specifically addressed in future studies.
Nanoparticles exhibit properties different from those of the same bulk materials leading to unkno... more Nanoparticles exhibit properties different from those of the same bulk materials leading to unknown toxicological implications that have evoked concern for (1) occupational, (2) consumer and (3) environmental safety. The current work utilizes epidemiological and toxicological data for screening level assessment of these risks using various suggested health relevant dose metrics (mass, particle number and surface area) to (i) quantify the potential risk levels and to (ii) compare the properties of these alternative risk assessment methods.
Nanoparticles exhibit properties different from those of the same bulk materials leading to unkno... more Nanoparticles exhibit properties different from those of the same bulk materials leading to unknown toxicological implications that have evoked concern for (1) occupational, (2) consumer and (3) environmental safety. The current work utilizes epidemiological and toxicological data for screening level assessment of these risks using various suggested health relevant dose metrics (mass, particle number and surface area) to (i) quantify
Several studies have reported laser printers as significant sources of nanosized particles (\0.1 ... more Several studies have reported laser printers as significant sources of nanosized particles (\0.1 lm). Laser printers are used occupationally in office environments and by consumers in their homes. The current work combines existing epidemiological and toxicological evidence on particlerelated health effects, measuring doses as mass, particle number and surface area, to estimate and compare the potential risks in occupational and consumer exposure scenarios related to the use of laser printers. The daily uptake of laser printer particles was estimated based on measured particle size distributions and lung deposition modelling. The obtained daily uptakes (particle mass 0.15-0.44 lg d -1 ; particle number 1.1-3.1 9 10 9 d -1 ) were estimated to correspond to 4-13 (mass) or 12-34 (number) deaths per million persons exposed on the basis of epidemiological risk estimates for ambient particles. These risks are higher than the generally used definition of acceptable risk of 1 9 10 -6 , but substantially lower than the estimated risks due to ambient particles. Toxicological studies on ambient particles revealed consistent values for lowest observed effect levels (LOELs) which were converted into equivalent daily uptakes using allometric scaling. These LOEL uptakes were by a factor of about 330-1,000 (mass) and 1,000-2,500 (particle surface area) higher than estimated uptakes from printers. This toxicological assessment would indicate no significant health risks due to printer particles. Finally, our study suggests that particle number (not mass) and mass (not surface area) are the most conservative risk metrics for the epidemiological and toxicological risks presented here, respectively.
Impact of neighbourhood on physical activity (PA) is under-investigated in European adolescents, ... more Impact of neighbourhood on physical activity (PA) is under-investigated in European adolescents, and few studies have used objective data on both exposures and outcomes. Therefore we investigated the association between objectively measured neighbourhood characteristics and PA in 15-year-old German adolescents. Study populations comprised of 688 adolescents residing in the urban Munich area and 504 from the rural Wesel area from the GINIplus and LISAplus birth cohorts. Neighbourhood was defined as a circular 500-m buffer around the residence. Greenness was calculated 1) as the mean Normalized Difference Vegetation Index (NDVI), and 2) as percent tree cover. Neighbourhood green spaces and sport and leisure facilities were defined as present or absent in a neighbourhood (data only available for Munich). Data on PA were collected from one-week triaxial accelerometry (hip-worn ActiGraph GT3X). Minutes of PA were classified into moderate-to-vigorous (MVPA), light and sedentary using Romanzini's et al. triaxial cutoffs, and averaged over the recording period. Activity diaries were used for differentiation between school and leisure (total minus school) PA. Area-specific associations were assessed by adjusted negative binomial regressions. In the Wesel area, residing in a neighbourhood with higher NDVI was associated with 9% more leisure MVPA among females and with 8% more leisure MVPA in rural dwellers. In the Munich area, residing in a neighbourhood with sport facilities was associated with 9% more leisure MVPA. The latter association was only significant in urban dwellers while neighbourhood leisure facilities increased MVPA in rural dwellers. Estimates were very similar when total MVPA was considered rather than solely leisure. There is indication that neighbourhood features could be associated with MVPA in German adolescents. However, different features seem to be important across sexes and in rural/urban settings, which need to be specifically addressed in future studies.
Nanoparticles exhibit properties different from those of the same bulk materials leading to unkno... more Nanoparticles exhibit properties different from those of the same bulk materials leading to unknown toxicological implications that have evoked concern for (1) occupational, (2) consumer and (3) environmental safety. The current work utilizes epidemiological and toxicological data for screening level assessment of these risks using various suggested health relevant dose metrics (mass, particle number and surface area) to (i) quantify the potential risk levels and to (ii) compare the properties of these alternative risk assessment methods.
Nanoparticles exhibit properties different from those of the same bulk materials leading to unkno... more Nanoparticles exhibit properties different from those of the same bulk materials leading to unknown toxicological implications that have evoked concern for (1) occupational, (2) consumer and (3) environmental safety. The current work utilizes epidemiological and toxicological data for screening level assessment of these risks using various suggested health relevant dose metrics (mass, particle number and surface area) to (i) quantify
Several studies have reported laser printers as significant sources of nanosized particles (\0.1 ... more Several studies have reported laser printers as significant sources of nanosized particles (\0.1 lm). Laser printers are used occupationally in office environments and by consumers in their homes. The current work combines existing epidemiological and toxicological evidence on particlerelated health effects, measuring doses as mass, particle number and surface area, to estimate and compare the potential risks in occupational and consumer exposure scenarios related to the use of laser printers. The daily uptake of laser printer particles was estimated based on measured particle size distributions and lung deposition modelling. The obtained daily uptakes (particle mass 0.15-0.44 lg d -1 ; particle number 1.1-3.1 9 10 9 d -1 ) were estimated to correspond to 4-13 (mass) or 12-34 (number) deaths per million persons exposed on the basis of epidemiological risk estimates for ambient particles. These risks are higher than the generally used definition of acceptable risk of 1 9 10 -6 , but substantially lower than the estimated risks due to ambient particles. Toxicological studies on ambient particles revealed consistent values for lowest observed effect levels (LOELs) which were converted into equivalent daily uptakes using allometric scaling. These LOEL uptakes were by a factor of about 330-1,000 (mass) and 1,000-2,500 (particle surface area) higher than estimated uptakes from printers. This toxicological assessment would indicate no significant health risks due to printer particles. Finally, our study suggests that particle number (not mass) and mass (not surface area) are the most conservative risk metrics for the epidemiological and toxicological risks presented here, respectively.
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Papers by Irene Brüske