Exploring absolute and relative measures of exposure to food environments in relation to dietary patterns among European adults.

OBJECTIVE: To explore the associations of absolute and relative measures of exposure to food retailers with dietary patterns, using simpler and more complex measures. DESIGN: Cross-sectional survey. SETTING: Urban regions in Belgium, France, Hungary, the Netherlands and the UK.ParticipantsEuropean adults (n 4942). Supermarkets and local food shops were classified as 'food retailers providing healthier options'; fast-food/takeaway restaurants, cafés/bars and convenience/liquor stores as 'food retailers providing less healthy options'. Simpler exposure measures used were density of healthy and density of less healthy food retailers. More complex exposure measures used were: spatial access (combination of density and proximity) to healthy and less healthy food retailers; density of healthier food retailers relative to all food retailers; and a ratio of spatial access scores to healthier and less healthy food retailers. Outcome measures were a healthy or less healthy dietary pattern derived from a principal component analysis (based on consumption of fruits, vegetables, fish, fast foods, sweets and sweetened beverages). RESULTS: Only the highest density of less healthy food retailers was significantly associated with the less healthy dietary pattern (ß = -129·6; 95 % CI -224·3, -34·8). None of the other absolute density measures nor any of the relative measures of exposures were associated with dietary patterns. CONCLUSIONS: More complex measures of exposure to food retailers did not produce stronger associations with dietary patterns. We had some indication that absolute and relative measures of exposure assess different aspects of the food environment. However, given the lack of significant findings, this needs to be further explored.

Patterns of childhood body mass index (BMI), overweight and obesity in South Asian and black participants in the English National child measurement programme: effect of applying BMI adjustments standardising for ethnic differences in BMI-body fatness associations.

BACKGROUND: The National Child Measurement Programme (NCMP) records weight and height and assesses overweight-obesity patterns in English children using body mass index (BMI), which tends to underestimate body fatness in South Asian children and overestimate body fatness in Black children of presumed African ethnicity. Using BMI adjustments to ensure that adjusted BMI was similarly related to body fatness in South Asian, Black and White children, we reassessed population overweight and obesity patterns in these ethnic groups in NCMP. METHODS: Analyses were based on 2012-2013 NCMP data in 582 899 children aged 4-5 years and 485 362 children aged 10-11 years. Standard centile-based approaches defined weight status in each age group before and after applying BMI adjustments for English South Asian and Black children derived from previous studies using the deuterium dilution method. FINDINGS: Among White children, overweight-obesity prevalences (boys, girls) were 23% and 21%, respectively, in 4-5 year olds and 33% and 30%, respectively, in 10-11 year olds. Before adjustment, South Asian children had lower overweight-obesity prevalences at 4-5 years (19%, 19%) and slightly higher prevalences at 10-11 years (42%, 34%), whereas Black children had higher overweight-obesity prevalences both at 4-5 years (31%, 29%) and 10-11 years (42%, 45%). Following adjustment, overweight-obesity prevalences were markedly higher in South Asian children both at 4-5 years (39%, 35%) and at 10-11 years (52%, 44%), whereas Black children had lower prevalences at 4-5 years (11%, 12%); at 10-11 years, prevalences were slightly lower in boys (32%) but higher in girls (35%). INTERPRETATION: BMI adjustments revealed extremely high overweight-obesity prevalences among South Asian children in England, which were not apparent in unadjusted data. In contrast, after adjustment, Black children had lower overweight-obesity prevalences except among older girls. FUNDING: British Heart Foundation, NIHR CLAHRC (South London), NIHR CLAHRC (North Thames).

Exploring the relationship between perceived barriers to healthy eating and dietary behaviours in European adults.

PURPOSE: Dietary behaviours may be influenced by perceptions of barriers to healthy eating. Using data from a large cross-European study (N = 5900), we explored associations between various perceived barriers to healthy eating and dietary behaviours among adults from urban regions in five European countries and examined whether associations differed across regions and socio-demographic backgrounds. METHODS: Frequency of consumption of fruit, vegetables, fish, fast food, sugar-sweetened beverages, sweets, breakfast and home-cooked meals were split by the median into higher and lower consumption. We tested associations between barriers (irregular working hours; giving up preferred foods; busy lifestyle; lack of willpower; price of healthy food; taste preferences of family and friends; lack of healthy options and unappealing foods) and dietary variables using multilevel logistic regression models. We explored whether associations differed by age, sex, education, urban region, weight status, household composition or employment. RESULTS: Respondents who perceived any barrier were less likely to report higher consumption of healthier foods and more likely to report higher consumption of fast food. 'Lack of willpower', 'time constraints' and 'taste preferences' were most consistently associated with consumption. For example, those perceiving lack of willpower ate less fruit [odds ratio (OR) 0.57; 95% confidence interval (CI) 0.50-0.64], and those with a busy lifestyle ate less vegetables (OR 0.54; 95% CI 0.47-0.62). Many associations differed in size, but not in direction, by region, sex, age and household composition. CONCLUSION: Perceived 'lack of willpower', 'time constraints' and 'taste preferences' were barriers most strongly related to dietary behaviours, but the association between various barriers and lower intake of fruit and vegetables was somewhat more pronounced among younger participants and women.

Improvements in the data quality of a national BMI measuring programme.

Variations in data collection between collecting regions can affect the outcome measures. This study examines the impact of improvements in data collection on outcome measures in a national monitoring programme between 2007/2008 and 2010/2011. Multilevel analysis of 2007/2008 and 2010/2011 National Child Measurement Programme (NCMP) data estimated the relationship between body mass index (BMI) z-score and data collection variations within coordinating regions, while adjusting for individual-level and school-level factors. The total sample was 2,013,285 students from 17,279 primary schools in 152 coordinating regions in England. Data collection differences accounted for 31.2% of the regional variation in BMI z-score for Reception (aged 4-5 years) students in 2007/2008; this reduced to 12.6% in 2010/2011. For Year 6 (aged 10-11 years) students, it reduced from 5.3% in 2007/2008 to 2.4% in 2010/2011. Digit preference in the rounding of weight measurements showed the largest decreases, from 27.3 to 4.5% for Reception year pupils and from 4.2 to 1.0% for Year 6 pupils. This demonstrates that improvements in data collection variation between regions in the NCMP have led to improvements in data quality.

The appraisal of public health interventions: an overview.

BACKGROUND: The approach currently used to appraise public health interventions is close to that of health technology appraisal for drugs. This approach is not appropriate for many public health interventions, however, when extremely small individual level benefits are delivered to extremely large populations. In many such situations, randomized controlled trials with sufficient size and power to determine individual level effects are impractical. Such interventions may be cost-effective, even in the absence of traditional evidence to demonstrate this. METHODS: We outline an alternative approach based on decision theory. We apply it to cases where prior beliefs are sufficiently strong and well grounded to allow decision-makers to assume the direction of change of the intervention's outcome, within the context of a transparent and deliberative decision-making process. Decision theory also assumes that decision-makers are risk neutral, implying that they should make decisions based on an intervention's mean cost-effectiveness, and should therefore disregard variance except when deciding to wait for more information. However, they must allow for biases. RESULTS: A framework is presented which has the potential to achieve large health gains at no additional cost. CONCLUSIONS: This analysis provides a rigorous theoretical framework for decision-makers in public health. The implied paradigm shift also applies to some clinically based areas.

Measuring the food and built environments in urban centres: reliability and validity of the EURO-PREVOB Community Questionnaire.

OBJECTIVES: The authors designed an instrument to measure objectively aspects of the built and food environments in urban areas, the EURO-PREVOB Community Questionnaire, within the EU-funded project 'Tackling the social and economic determinants of nutrition and physical activity for the prevention of obesity across Europe' (EURO-PREVOB). This paper describes its development, reliability, validity, feasibility and relevance to public health and obesity research. STUDY DESIGN: The Community Questionnaire is designed to measure key aspects of the food and built environments in urban areas of varying levels of affluence or deprivation, within different countries. The questionnaire assesses (1) the food environment and (2) the built environment. METHODS: Pilot tests of the EURO-PREVOB Community Questionnaire were conducted in five to 10 purposively sampled urban areas of different socio-economic status in each of Ankara, Brno, Marseille, Riga, and Sarajevo. Inter-rater reliability was compared between two pairs of fieldworkers in each city centre using three methods: inter-observer agreement (IOA), kappa statistics, and intraclass correlation coefficients (ICCs). RESULTS: Data were collected successfully in all five cities. Overall reliability of the EURO-PREVOB Community Questionnaire was excellent (inter-observer agreement (IOA) > 0.87; intraclass correlation coefficients (ICC)s > 0.91 and kappa statistics > 0.7. However, assessment of certain aspects of the quality of the built environment yielded slightly lower IOA coefficients than the quantitative aspects. CONCLUSIONS: The EURO-PREVOB Community Questionnaire was found to be a reliable and practical observational tool for measuring differences in community-level data on environmental factors that can impact on dietary intake and physical activity. The next step is to evaluate its predictive power by collecting behavioural and anthropometric data relevant to obesity and its determinants.

Age differences in the association of childhood obesity with area-level and school-level deprivation: cross-classified multilevel analysis of cross-sectional data.

OBJECTIVE: Evidence suggests that area-level deprivation is associated with obesity independently of individual socioeconomic status; however, although the school may also have an impact on child health, few studies have investigated the association between school-level deprivation and the body mass index (BMI) of students. The aim of this study was to assess the relationship between the BMI for children of different ages and area-level and school-level deprivation. SUBJECTS: BMI measurements were collected through the National Child Measurement Programme (NCMP) that samples from two school years: 396,171 reception year pupils (4-5-year olds) and 392,344 year 6 pupils (10-11-year olds) from 14,054 primary schools in England. DESIGN: Cross-classified multilevel models with four levels: individual (n=788,525), lower super output areas corresponding to area of residence (n=29,606), schools (n=14,054) and primary care trusts (PCTs, n=143), which coordinate the collection of data within a large area, were used to study the relationship between measures of deprivation at an area and school level, and childhood BMI within England. RESULTS: A positive association was found between the area and school measures of deprivation, and student BMI. Both the measures of deprivation explained a greater proportion of variance in BMI z-scores for year 6 students than for the reception year students, with a greater difference between the year groups found with the school-level measure of socioeconomic status than for the the area-level measure. CONCLUSIONS: Deprivation explains a greater proportion of the variance in BMI for older compared with younger children, perhaps reflecting the impact of deprivation as children age, highlighting the widening of health inequalities through childhood. The association with school-level deprivation illustrates the impact of the school on BMI status throughout the primary school years.

Changes in waist circumference among adolescents in England from 1977-1987 to 2005-2007.

OBJECTIVE: To assess change in abdominal obesity in adolescents in England. STUDY DESIGN: Health Survey for England (HSE), annual cross-sectional surveys of nationally representative samples in England. METHODS: This study included 1770 children aged 11-16 years in HSE 2005-2007 with valid waist circumference (WC) measurements. WC and body mass index (BMI) were expressed as standard deviation scores (z scores) against the growth references used for British children. RESULTS: Mean WC z scores were substantially higher than mean BMI z scores for both sexes: WC 1.0 [95% confidence interval (CI) 0.93-1.1], BMI 0.54 (95% CI 0.44-0.63) for boys; WC 1.3 (95% CI 1.2-1.4), BMI 0.48 (95% CI 0.40-0.56) for girls (both P < 0.001). Mean WC z score was higher for girls than boys (P < 0.001). Between 1997 and 2005-2007, WC increased for both boys (P < 0.01) and girls (P < 0.001), but BMI did not (P > 0.05). Only children in the lowest WC decile had an increase in WC z score less than +1 standard deviation compared with the 1977-1987 baseline. BMI z score increased across the top nine deciles of the BMI distribution by 0.4 (2nd-4th deciles) to 0.9 (top decile). CONCLUSIONS: WC in adolescents has increased substantially, and probably more than BMI. The whole population has become fatter.

Who owns the roads? How motorised traffic discourages walking and bicycling.

OBJECTIVE: To examine the impact of traffic on levels of walking and bicycling. METHOD: Review of the literature of medical, public health, city planning, public administration and traffic engineering. RESULTS: The real and perceived danger and discomfort imposed by traffic discourage walking and bicycling. Accurately or not, pedestrians and bicyclists judge injury risk and respond accordingly. Although it can be difficult to measure these effects, observed behaviour provides good evidence for these effects, with the strongest association being an inverse correlation between volumes and speeds of traffic and levels of walking and cycling. CONCLUSION: Interventions to reduce traffic speed and volume are likely to promote walking and bicycling and thus result in public health gains.

The relation between sleep duration and sedentary behaviours in European adults.

Too much sitting, and both short and long sleep duration are associated with obesity, but little is known on the nature of the relations between these behaviours. We therefore examined the associations between sleep duration and time spent sitting in adults across five urban regions in Europe. We used cross-sectional survey data from 6,037 adults (mean age 51.9 years (SD 16.4), 44.0% men) to assess the association between self-reported short (<6 h per night), normal (6-8 h per night) and long (>8 h per night) sleep duration with self-report total time spent sitting, time spent sitting at work, during transport, during leisure and while watching screens. The multivariable multilevel linear regression models were tested for moderation by urban region, age, gender, education and weight status. Because short sleepers have more awake time to be sedentary, we also used the percentage of awake time spent sedentary as an outcome. Short sleepers had 26.5 min day(-1) more sedentary screen time, compared with normal sleepers (CI 5.2; 47.8). No statistically significant associations were found with total or other domains of sedentary behaviour, and there was no evidence for effect modification. Long sleepers spent 3.2% higher proportion of their awake time sedentary compared with normal sleepers. Shorter sleep was associated with increased screen time in a sample of European adults, irrespective of urban region, gender, age, educational level and weight status. Experimental studies are needed to assess the prospective relation between sedentary (screen) time and sleep duration.

Psychosocial environment: definitions, measures and associations with weight status--a systematic review.

Socio-ecological models suggest that many elements of the social environment act as upstream determinants of obesity. This systematic review examined definitions, measures and strength of associations between the psychosocial environment and adult weight status. Studies were included if they were conducted on adults, the outcome was weight status, carried out in any developed country and investigated at least one psychosocial environmental construct. Six databases for primary studies were searched: EMBASE, MEDLINE, PsycINFO, Scopus, Web of Science and the Cochrane Library. We restricted our search to studies published in English between January 1995 and February 2015. An adapted 'Quality Assessment Tool for Quantitative Studies' was used to evaluate risk of bias of included studies. Out of 14,784 screened records, 42 articles were assessed using full text. A total of 19 studies were included. The strongest associations with weight status were found for social capital and collective efficacy, although few studies found significant associations. There was heterogeneity in the definitions and metrics of psychosocial environmental constructs. There is limited evidence that greater social capital and collective efficacy are associated with healthier weight status. The research conducted to date has not robustly identified relations. We highlight challenges to undertaking research and establishing causality in this field and provide recommendations for further research.

Self-defined residential neighbourhoods: size variations and correlates across five European urban regions.

The neighbourhood is recognized as an important unit of analysis in research on the relation between obesogenic environments and development of obesity. One important challenge is to define the limits of the residential neighbourhood, as perceived by study participants themselves, in order to improve our understanding of the interaction between contextual features and patterns of obesity. An innovative tool was developed in the framework of the SPOTLIGHT project to identify the boundaries of neighbourhoods as defined by participants in five European urban regions. The aims of this study were (i) to describe self-defined neighbourhood (size and overlap with predefined residential area) according to the characteristics of the sampling administrative neighbourhoods (residential density and socioeconomic status) within the five study regions and (ii) to determine which individual or/and environmental factors are associated with variations in size of self-defined neighbourhoods. Self-defined neighbourhood size varies according to both individual factors (age, educational level, length of residence and attachment to neighbourhood) and contextual factors. These findings have consequences for how residential neighbourhoods are defined and operationalized and can inform how self-defined neighbourhoods may be used in research on associations between contextual characteristics and health outcomes such as obesity.

Neighbourhood typology based on virtual audit of environmental obesogenic characteristics.

Virtual audit (using tools such as Google Street View) can help assess multiple characteristics of the physical environment. This exposure assessment can then be associated with health outcomes such as obesity. Strengths of virtual audit include collection of large amount of data, from various geographical contexts, following standard protocols. Using data from a virtual audit of obesity-related features carried out in five urban European regions, the current study aimed to (i) describe this international virtual audit dataset and (ii) identify neighbourhood patterns that can synthesize the complexity of such data and compare patterns across regions. Data were obtained from 4,486 street segments across urban regions in Belgium, France, Hungary, the Netherlands and the UK. We used multiple factor analysis and hierarchical clustering on principal components to build a typology of neighbourhoods and to identify similar/dissimilar neighbourhoods, regardless of region. Four neighbourhood clusters emerged, which differed in terms of food environment, recreational facilities and active mobility features, i.e. the three indicators derived from factor analysis. Clusters were unequally distributed across urban regions. Neighbourhoods mostly characterized by a high level of outdoor recreational facilities were predominantly located in Greater London, whereas neighbourhoods characterized by high urban density and large amounts of food outlets were mostly located in Paris. Neighbourhoods in the Randstad conurbation, Ghent and Budapest appeared to be very similar, characterized by relatively lower residential densities, greener areas and a very low percentage of streets offering food and recreational facility items. These results provide multidimensional constructs of obesogenic characteristics that may help target at-risk neighbourhoods more effectively than isolated features.

Mismatch between perceived and objectively measured environmental obesogenic features in European neighbourhoods.

Findings from research on the association between the built environment and obesity remain equivocal but may be partly explained by differences in approaches used to characterize the built environment. Findings obtained using subjective measures may differ substantially from those measured objectively. We investigated the agreement between perceived and objectively measured obesogenic environmental features to assess (1) the extent of agreement between individual perceptions and observable characteristics of the environment and (2) the agreement between aggregated perceptions and observable characteristics, and whether this varied by type of characteristic, region or neighbourhood. Cross-sectional data from the SPOTLIGHT project (n = 6037 participants from 60 neighbourhoods in five European urban regions) were used. Residents' perceptions were self-reported, and objectively measured environmental features were obtained by a virtual audit using Google Street View. Percent agreement and Kappa statistics were calculated. The mismatch was quantified at neighbourhood level by a distance metric derived from a factor map. The extent to which the mismatch metric varied by region and neighbourhood was examined using linear regression models. Overall, agreement was moderate (agreement < 82%, kappa < 0.3) and varied by obesogenic environmental feature, region and neighbourhood. Highest agreement was found for food outlets and outdoor recreational facilities, and lowest agreement was obtained for aesthetics. In general, a better match was observed in high-residential density neighbourhoods characterized by a high density of food outlets and recreational facilities. Future studies should combine perceived and objectively measured built environment qualities to better understand the potential impact of the built environment on health, particularly in low residential density neighbourhoods.

Exploring why residents of socioeconomically deprived neighbourhoods have less favourable perceptions of their neighbourhood environment than residents of wealthy neighbourhoods.

Residents of socioeconomically deprived areas perceive their neighbourhood as less conducive to healthy behaviours than residents of more affluent areas. Whether these unfavourable perceptions are based on objective neighbourhood features or other factors is poorly understood. We examined individual and contextual correlates of socioeconomic inequalities in neighbourhood perceptions across five urban regions in Europe. Data were analysed from 5205 participants of the SPOTLIGHT survey. Participants reported perceptions of their neighbourhood environment with regard to aesthetics, safety, the presence of destinations and functionality of the neighbourhood, which were summed into an overall neighbourhood perceptions score. Multivariable multilevel regression analyses were conducted to investigate whether the following factors were associated with socioeconomic inequalities in neighbourhood perceptions: objectively observed neighbourhood features, neighbourhood social capital, exposure to the neighbourhood, self-rated health and lifestyle behaviours. Objectively observed traffic safety, aesthetics and the presence of destinations in the neighbourhood explained around 15% of differences in neighbourhood perceptions between residents of high and low neighbourhoods; levels of neighbourhood social cohesion explained around 52%. Exposure to the neighbourhood, self-rated health and lifestyle behaviours were significant correlates of neighbourhood perceptions but did not contribute to socioeconomic differences. This cross-European study provided evidence that socioeconomic differences in neighbourhood perceptions are not only associated with objective neighbourhood features but also with social cohesion. Levels of physical activity, sleep duration, self-rated health, happiness and neighbourhood preference were also associated with neighbourhood perceptions.

Interactions of individual perceived barriers and neighbourhood destinations with obesity-related behaviours in Europe.

Perceived barriers towards physical activity and healthy eating as well as local availability of opportunities (destinations in the neighbourhood) are important determinants of obesity-related behaviours in adults. Little is known, however, about how these factors interact with the behaviours. Data were analysed from 5,205 participants of the SPOTLIGHT survey, conducted in 60 neighbourhoods in urban regions of five different countries across Europe. A virtual audit was conducted to collect data on the presence of destinations in each neighbourhood. Direct associations of, and interactions between, the number of individual perceived barriers and presence of destinations with obesity-related behaviours (physical activity and dietary behaviours) were analysed using multilevel regression analyses, adjusted for key covariates. Perceiving more individual barriers towards physical activity and healthy eating was associated with lower odds of physical activity and healthy eating. The presence of destinations such as bicycle lanes, parks and supermarkets was associated with higher levels of physical activity and healthier dietary behaviours. Analyses of additive interaction terms suggested that the interaction of destinations and barriers was competitive, such that the presence of destinations influenced obesity-related behaviours most among those perceiving more barriers. These explorative findings emphasize the interest and importance of combining objective (e.g. virtual neighbourhood audit) methods and subjective (e.g. individual perceived barriers collected in a survey) to better understand how the characteristics of the residential built environment can shape obesity-related behaviours depending on individual characteristics.

Neighbourhood social capital: measurement issues and associations with health outcomes.

We compared ecometric neighbourhood scores of social capital (contextual variation) to mean neighbourhood scores (individual and contextual variation), using several health-related outcomes (i.e. self-rated health, weight status and obesity-related behaviours). Data were analysed from 5,900 participants in the European SPOTLIGHT survey. Factor analysis of the 13-item social capital scale revealed two social capital constructs: social networks and social cohesion. The associations of ecometric and mean neighbourhood-level scores of these constructs with self-rated health, weight status and obesity-related behaviours were analysed using multilevel regression analyses, adjusted for key covariates. Analyses using ecometric and mean neighbourhood scores, but not mean neighbourhood scores adjusted for individual scores, yielded similar regression coefficients. Higher levels of social network and social cohesion were not only associated with better self-rated health, lower odds of obesity and higher fruit consumption, but also with prolonged sitting and less transport-related physical activity. Only associations with transport-related physical activity and sedentary behaviours were associated with mean neighbourhood scores adjusted for individual scores. As analyses using ecometric scores generated the same results as using mean neighbourhood scores, but different results when using mean neighbourhood scores adjusted for individual scores, this suggests that the theoretical advantage of the ecometric approach (i.e. teasing out individual and contextual variation) may not be achieved in practice. The different operationalisations of social network and social cohesion were associated with several health outcomes, but the constructs that appeared to represent the contextual variation best were only associated with two of the outcomes.

Chronic effects of dietary exposure to amosite asbestos and tremolite in F344 rats.

Carcinogenesis bioassays of blocky (nonfibrous) tremolite and amosite asbestos alone or in combination with the intestinal carcinogen 1,2-dimethylhydrazine dihydrochloride (DMH) were conducted with male and female Fischer 344 rats. The minerals were administered at a concentration of 1% in pelleted diet for the entire lifetime of the rats starting with the dams of the test animals. One group of amosite rats also received chrysotile asbestos via gavage during lactation. Group sizes varied from 100 to 250 animals. The offspring from mothers exposed to tremolite or amosite asbestos were smaller at weaning than those from untreated mothers and remained smaller throughout their life. The administration of dimethylhydrazine (DMH) did not affect body weight gain, either in amosite-exposed or nonexposed animals. Survival was comparable in the tremolite and control groups. The amosite-exposed rats showed enhanced survival compared to the untreated controls. DMH exposure reduced survival by approximately one year, although the amosite plus DMH groups survived slightly better than the DMH alone groups. No toxicity or increase in neoplasia was observed in the tremolite-exposed rats compared to the controls. Significant increases (p less than 0.05) in the rates of C-cell carcinomas of the thyroid and monocytic (mononuclear cell) leukemia in male rats were observed in amosite-exposed groups. However, the biological significance of the C-cell carcinomas in relation to amosite asbestos exposure is discounted because of a lack of significance when C-cell adenomas and carcinomas were combined and the positive effect was not observed in the amosite plus preweaning gavage group. The biological significance of an increased incidence of mononuclear cell leukemia is questionable, because of a lack of statistical significance in the amosite group when evaluated using life table analysis, lack of significance when compared to the tremolite control group, and the fact that no toxic or neoplastic lesions were observed in the target organs, i.e., gastrointestinal tract and mesothelium. DMH caused a high rate of (62-74%) of intestinal neoplasia in amosite and nonamosite-exposed groups. Neither an enhanced carcinogenic nor protective effect was demonstrated by exposure to amosite asbestos.