Reproducibility of diagnostic criteria associated with atypical breast cytology.

OBJECTIVE: The aim of this project was to assess the interobserver and intraobserver variability when identifying cytological criteria, which were found to have a statistically significant association with C3 within a workplace environment. METHODS: Sixty C3 cases with known endpoints of malignant, benign proliferative or benign non-proliferative diagnoses were blindly and independently screened by seven experienced cytologists to identify previously reported statistically significant criteria associated with the C3 category. The criteria included the presence of myoepithelial cells or bare bipolar nuclei, cohesiveness, cystic background, papillary fragments with fibrovascular cores and tubular structures. Kappa statistics were used to measure interobserver variability. Two cytologists repeated the process 6 months later to obtain intraobserver data. RESULTS: The interobserver agreement was poor for all criteria except tubules which performed badly. The intraobserver variability for the two cytologists showed that one cytologist achieved moderate intraobserver agreement for all the criteria except cohesion which was poor, whilst the second cytologist showed poor agreement for all criteria. The reasons for the variability are multifactorial and include threshold effects where criteria lack good definition or error in identifying the criteria. CONCLUSION: Interobserver and intraobserver variability remains a significant challenge for cytologists. Despite attempts to define significant criteria associated with C3, good reproducibility could not be achieved. The C3 category is imprecise and highlights the inadequacy of the current classification reporting categories for breast FNA. The impending review of reporting breast cytology by the International Academy of Cytology is timely and appropriate.

Heads Up: a pilot trial of a psychological intervention to improve nutrition in head and neck cancer patients undergoing radiotherapy.

Malnutrition in head and neck cancer (HNC) patients is common and associated with poorer radiotherapy outcomes including increased mortality. This pilot trial investigates the feasibility and effectiveness of a psychological intervention to improve nutritional status, depression and mortality in HNC patients undergoing radiotherapy. Fifty-nine intervention patients received motivational interviewing and cognitive behavioural therapy compared to 70 historical controls who received treatment as usual. Participants were assessed for nutrition, depression and mortality. There were no significant differences between groups in nutritional status, depression or mortality. Subgroup analyses among patients at greater nutritional risk (cancers of the oral cavity, pharynx, larynx) revealed a potentially clinically important reduction on the PG-SGA and lower mortality (31% of controls vs. 16% intervention; P = 0.03) in favour of the intervention condition. Potential benefits in nutritional status and in mortality in this pilot trial of a psychological intervention among HNC patients at high nutritional risk suggest that a larger randomised controlled trial is warranted.

Assessment of dietary fat intake and innate immune activation as risk factors for impaired lung function.

BACKGROUND/OBJECTIVES: Preservation of lung health with aging is an important health issue in the general population, as loss of lung function with aging can lead to the development of obstructive lung disease and is a predictor of all-cause and cardiovascular mortality. Inflammation is increasingly linked to loss of lung function and evidence suggests that consumption of dietary fat exacerbates inflammation. We aimed to determine the association between dietary fat intake and lung function in older people. SUBJECTS/METHODS: Participants from the Hunter community study, a population-based cohort, were recruited during 2004 and 2005. Participants received a clinical assessment, including spirometry, and provided a blood sample. Diets were analyzed using food-frequency questionnaires. Plasma interleukin (IL)-6 and C-reactive protein was measured by Enzyme-Linked immunosorbent assay. RESULTS: Using backward stepwise linear regression, %energy from dietary fat, age and plasma IL-6 were considered as negative predictors of forced expiratory volume in one second (FEV(1)) in men. Also in men, % energy intake from dietary fat, age, body mass index and IL-6 were negative predictors of %predicted forced vital capacity (FVC). Smoking and age were negative predictors of FEV(1)/FVC. In women, plasma IL-6 and age were negative predictors of %FVC, whereas obesity was positively associated with FEV(1)/FVC. CONCLUSIONS: An increased proportion of fat in the diet is associated with the reduced lung function in older men. Dietary-fat induced innate immune activation and IL-6 release may contribute to this effect. Dietary interventions involving fat restriction should be further investigated as means of preserving lung function with aging.

Pleasure or pain? A profile of smokers in Northern England.

OBJECTIVE: To construct a profile of smokers using multiple indices of physical, mental and social health. STUDY DESIGN: Cross-sectional study. METHODS: The setting was Wigan and Bolton Health Authority, an urban district in the North West of England. A random sample of over 15000 adults from the Health Authority adult population completed a written questionnaire. Prevalence ratios were calculated for physical, mental and social health indicators for smokers compared with non-smokers, adjusted for borough, age and deprivation score of place of residence. RESULTS: Smokers were less likely to report their current health as good, and reported a significantly higher prevalence of arthritis, bronchitis, backache and respiratory symptoms. Smokers had more mobility problems and recent severe pain. Smokers had less healthy lifestyles across many behaviours (e.g. poorer diet, taking less regular exercise and more problem drinking). Depression and the proportion of people with a high psychiatric morbidity score were increased. More women smokers reported a lack of social support, and smokers more often reported financial difficulties. Differences were exaggerated by comparing heavy smokers with non-smokers. CONCLUSIONS: Independent of the level of deprivation of their area of residence, smokers have poorer physical, social and mental health, with a dose-response effect. Smoking creates considerable pain, but little evidence of pleasure.

Does routine assessment and real-time feedback improve cancer patients' psychosocial well-being?

This study examined the effectiveness of giving medical oncologists immediate feedback about cancer patients' self-reported psychosocial well-being in reducing those patients' levels of anxiety, depression, perceived needs and physical symptoms. Cancer patients attending one cancer centre for their first visit were allocated to intervention (n = 42) or control (n = 38) groups. All patients completed a computerized survey assessing their psychosocial well-being while waiting to see the oncologist. Intervention patients' responses were immediately scored and summary reports were placed in each patient's file for follow-up. A total of 48 participants (25 intervention and 23 control) completed the survey four times. Intervention patients who reported a debilitating physical symptom at visit 2 were significantly less likely to report a debilitating physical symptom at visit 3 compared with control patients (OR = 2.8, P = 0.04). Reductions in levels of anxiety, depression and perceived needs among intervention patients were not significantly different to control patients. Repeated collection and immediate feedback of patient-reported health information to oncologists has potential to improve patients' symptom control, but has little impact upon emotional well-being, including those at high risk. Future research should consider providing the feedback to other health professionals and patients, and monitor the impact on the process of individual patient care.

Deprivation and trends in blood pressure, cholesterol, body mass index and smoking among participants of a UK primary care-based cardiovascular risk factor screening programme: both narrowing and widening in cardiovascular risk factor inequalities.

OBJECTIVES: To examine recent time trends in blood pressure (BP), total cholesterol, body mass index (BMI) and current smoking among people in the UK of different deprivation groups. DESIGN: Repeatable survey. SETTING: Primary care-based UK cardiovascular risk factor screening programme (58 Stockport general practices). PARTICIPANTS: 37,161 women and 33,977 men aged 35-60 years responding to a screening invitation and with a first screening episode during 1989-99. RESULTS: There were significant decreasing trends in total cholesterol (-0.06 mmol/l/year, 95% confidence interval (CI) -0.07 to -0.06 for women, -0.07 mmol/l/year, 95% CI -0.07 to -0.06 for men), with a significantly faster drop in more deprived groups (-0.005 mmol/year/increasing deprivation group, 95% CI -0.01 to -0.001 for both sexes). There were decreasing trends in current smoking prevalence (odds ratio (OR) 0.97/year, 95% CI 0.96 to 0.97 for women, OR 0.96/year, 95% CI 0.95 to 0.96 for men) with a significantly slower drop in the more deprived groups (OR 1.01/year/increasing deprivation group, 95% CI 1.00 to 1.01 for both sexes). There were significant increasing trends in BMI (0.11 kg/m(2)/year in women, 95% CI 0.09 to 0.13, 0.10 kg/m(2)/year in men, 95% CI 0.08 to 0.11), with a significantly slower increase in the more deprived groups among men only (-0.02 kg/m(2)/year/increasing deprivation group, 95% CI -0.01 to -0.03). Inequality in BP narrowed among men but widened among women. CONCLUSION: Inequalities in risk factors between different deprivation groups may be both widening (smoking, BP in women) and narrowing (total cholesterol, BMI and BP in men). Given baseline inequalities in risk factors levels, these trends suggest that inequalities in cardiovascular disease are likely to persist in the future.

Second-hand smoke levels in UK pubs and bars: do the English Public Health White Paper proposals go far enough?

BACKGROUND: The English Public Health White Paper proposes introducing smoke-free workplaces except in pubs and bars that do not prepare and serve food. The bar area will be non-smoking in exempted pubs. OBJECTIVE: To explore the likely impact of these proposals in UK pubs and bars. METHODS: A total of 59 pubs and bars within Greater Manchester in 2001 were chosen. Thirteen were mechanically ventilated, 12 were naturally ventilated and 34 had extractor fans; 23 provided non-smoking areas. We measured time-weighted average concentrations of respirable suspended particles (RSP), solanesol tobacco-specific particles and vapour-phase nicotine (VPN) over a 4-h sampling period on a Tuesday or Saturday night. RESULTS: Second-hand smoke (SHS) levels in smoking areas were high (mean RSP 114.5 microg/m3, VPN 88.2 microg/m3, solanesol 101.7 microg/m3). There were only small (5-13 per cent) reductions in bar areas. Mean levels were lower in non-smoking areas: by 33 per cent for RSPs, 52 per cent for solanesol particles and 69 per cent for VPN. Compared with other settings (homes and other workplaces) with unrestricted smoking, mean SHS levels were high throughout all areas of the pubs regardless of ventilation strategy. CONCLUSION: Partial measures, like those in the English Public Health White Paper, will leave bar staff in exempted pubs unprotected from the occupational hazard of SHS.

Planning to win: Health and lifestyles associated with physical activity amongst 15,423 adults.

STUDY OBJECTIVE: To assess levels of physical activity in the general population and amongst the 'healthy', and to identify factors associated with this important health behaviour. DESIGN: Population-based cross-sectional study. SETTING: North-west England. PARTICIPANTS: Adults (aged at least 18 years) registered with a general practitioner with a residential address within two local administrative districts (local authorities). MAIN RESULTS: Less than one-third of adults performed adequate amounts of physical activity for health protection, and this differed little when analyses were restricted to 'healthy' people. Lower levels of physical activity were observed amongst women, older people, ethnic groups, those with obesity and in each increased quintile of social deprivation. Current smokers, but not previous smokers, were less likely to be physically active, as were those not eating at least five portions of fruit and vegetables per day. Lack of physical activity was associated with poor general health and a history of, or current, chronic disease. CONCLUSIONS: Concerted efforts are required by the Government, society and individuals to overturn our predominantly physically inactive adult population. Interventions may be needed which specifically target certain groups, especially the most socially deprived, and that consider individuals and societal barriers to becoming physically active. Evidence of the effectiveness of individual and population-based interventions remains scant and this needs to be addressed urgently.

Absence of socioeconomic variation in survival from colorectal cancer in patients receiving surgical treatment in one health district: cohort study.

OBJECTIVE: To examine whether there is an association between patient deprivation status and survival from colorectal cancer among patients receiving treatment of the same type and quality. PATIENTS AND METHODS: A survival study was conducted of all colorectal cancer patients diagnosed between 1991 and 1997 who received surgery either in the NHS district general hospital or the private hospital of one UK health district. The five-year survival rates, both all cause and colorectal cancer specific, were calculated for subgroups defined by patient age, gender, stage and deprivation status using Kaplan-Meier curves. Cox proportional hazards models were used to examine the influence of deprivation on five-year survival after adjusting for age, gender and stage. RESULTS: There were 603 consecutive colorectal patients during the study period. Five-year all-cause and colorectal cancer-specific survival rates were 41% and 53%, respectively. There was no association between deprivation status and stage at diagnosis (P = 0.308). Multivariable proportional hazards modelling (adjusting for gender, age and tumour stage) demonstrated no association between deprivation status and survival. CONCLUSION: In this single district study, no relationship between patient socioeconomic status and survival from colorectal cancer could be demonstrated. Consistency in the type and quality of treatment offered to patients by the same clinical teams may have been responsible for the equitable survival outcomes.

Current smoking and the risk of non-fatal myocardial infarction in the WHO MONICA Project populations.

BACKGROUND: Cohort studies have shown that smoking has a substantial influence on coronary heart disease mortality in young people. Population based data on non-fatal events have been sparse, however. OBJECTIVE: To study the impact of smoking on the risk of non-fatal acute myocardial infarction (MI) in young middle age people. METHODS: From 1985 to 1994 all non-fatal MI events in the age group 35-64 were registered in men and women in the WHO MONICA (multinational monitoring of trends and determinants in cardiovascular disease) project populations (18,762 events in men and 4047 in women from 32 populations from 21 countries). In the same populations and age groups 65,741 men and 66,717 women participated in the surveys of risk factors (overall response rate 72%). The relative risk of non-fatal MI for current smokers was compared with non-smokers, by sex and five year age group. RESULTS: The prevalence of smoking in people aged 35-39 years who experienced non-fatal MI events was 81% in men and 77% in women. It declined with increasing age to 45% in men aged 60-64 years and 36% in women, respectively. In the 35-39 years age group the relative risk of non-fatal MI for smokers was 4.9 (95% confidence interval (CI) 3.9 to 6.1) in men and 5.3 (95% CI 3.2 to 8.7) in women, and the population attributable fractions were 65% and 55%, respectively. CONCLUSIONS: During the study period more than half of the non-fatal MIs occurring in young middle age people can be attributed to smoking.

Secondary screening for osteoporosis in patients admitted with minimal-trauma fracture to a major teaching hospital.

AIMS: The aim of the present study was to determine: (i) the prevalence of the investigation and treatment of osteoporosis in patients admitted to hospital with a minimal-trauma fracture, (ii) the prevalence of osteoporosis using bone mineral density assessment by dual X-ray absorptiometry (DEXA) in such patients and (iii) a clinical pathway for the management of osteoporosis in such patients. METHODS: A cross-sectional study was undertaken involving all patients admitted with a fracture to Westmead Hospital, Sydney, Australia, between January 1999 and June 2000 (n = 327). Of these, 264 were excluded because of: (i) the fracture following significant trauma (n = 83), (ii) unavailability of medical records for review (n = 38), (iii) nursing home status (n = 37), (iv) previous malignancy (n = 18), (v) deceased (n = 11), (vi) recent osteoporosis screening and/or treatment (n = 18), (vii) refusal to participate (n = 37), (viii) uncontactable (n = 16) and (ix) inadequate English (n = 6). The remaining 63 patients underwent DEXA assessment and the following laboratory investigations: (i) liver function tests, (ii) urea, (iii) electrolytes, (iv) calcium, (v) phosphate, (vi) full blood count, (v) 25-hydroxyvitamin D level and (vi) thyroid-function tests. In men, levels of serum free testosterone, luteinizing hormone, follicle-stimulating hormone and prolactin were also obtained. RESULTS: Of the 63 study participants, 87% of the 47 women were either osteoporotic (T <-2.5) or osteopenic (-2.5

Self-blood-pressure monitoring--a questionnaire study: response, requirement, training, support-group popularity and recommendations.

The objective of this study was to survey hypertensive patients' response to, requirement for and training in self-blood pressure monitoring (SBPM). A total of 222 hypertensives were invited to complete a questionnaire even when not participating in the project. Questions supplied information on demographics, monitoring frequency, convenience of attending the surgery, monitor ownership and preference for and ease of self-monitoring. Comments supplied qualitative data. Training group questionnaires supplied similar data as well as SBPM data before and after training. Of 133 respondents, a higher educated, younger, wider age range wanted to participate (76; 57.2%) and tended to self-monitor. However, only an increase in further education (FE) was associated with an increased probability of participation and inclination to self-monitor in the multivariate analyses. A positive relationship exists between age and frequency in both groups. About a sixth of respondents own monitors and ownership is correlated to FE. Although most patients found it convenient to visit the surgery, the percentage finding it convenient was lower in patients attending training sessions than in the original survey, possibly indicating that independence is important for SBPM. Younger, higher-educated patients tended to self-monitor although FE was again the significant factor. Training increased preference for the idea of SBPM, prospective monitor ownership (64.8% of non-owners) and self-monitoring intention (76.1%). Patients found recording card listed cardiovascular disease (CVD) risks valuable and 69.6% (32) wanted to establish a support group. Comments and interviews indicated haphazard knowledge, routines and uncertainty about SBPM. A standardised procedure including patient assessment, SBPM protocol and lifestyle education is needed for SBPM to be successful.

Opportunities for control of coronary heart disease in Australia.

OBJECTIVE: To estimate the number of coronary events that could be prevented in Australia each year by the use of preventive and therapeutic strategies targeted to subgroups of the population based on their levels of risk and need. METHODS: Estimates of risk reduction from the published literature, prevalence estimates of elevated risk factor levels from the 1995 National Health Survey and treatment levels from the Australian collaborating centres in the World Health Organization's MONICA Project were used to calculate numbers of coronary events preventable among men and women aged 35-79 years in Australia. RESULTS: Approximately 14,000 coronary events could be avoided each year if the mean level of cholesterol in the population was reduced by 0.5 mmol/L, smoking prevalence was halved and prevalence of physical inactivity was reduced to 25%. This represents a reduction in coronary events of about 40%. Even with less optimistic targets, a reduction of 20% could be attained, while the achievement of some internationally recommended targets could lead to almost 50% reduction. In the short term, aggressive medical treatment of people with elevated levels of risk factors and established coronary disease offers the greatest opportunity for reducing coronary events. CONCLUSION: A comprehensive approach to reduce levels of behavioural and biological risk factors and improve the use of effective treatment could lead to a large reduction in coronary event rates. In the long term, primary prevention--especially to reduce smoking, lower cholesterol levels and increase exercise--has the potential to reduce the population levels of risk and hence contain the national cost of coronary disease.

Case fatality after an acute cardiac event: the effect of smoking and alcohol consumption.

The objective of this study was to use a population-based register of acute cardiac events to investigate the association between survival after an acute event and history of smoking and alcohol consumption. The population was all residents of the Lower Hunter Region of Australia aged 25 to 69 years who suffered myocardial infarction or sudden cardiac death between 1986 and 1994. Among 10,170 events, 2504 resulted in death within 28 days. After adjusting for sex, age and medical history, current smokers had a similar risk of dying after an acute cardiac event to never-smokers [odds ratio (OR)=1.10, 95% confidence interval (CI) 0.94-1.29]. People who consumed more than 8 alcoholic drinks per day on more than 2 days per week (OR=1.93, 95% CI 1.39-2.69) and former moderate to heavy drinkers (OR=4.59, 95% CI 3.65-5.76) were more likely to die than people who were nondrinkers. The results of this large community study, suggesting no effect of smoking on case fatality and an increased risk of death after an acute cardiac event for heavy drinkers and former moderate to heavy drinkers, highlight the importance of a population view of case fatality. These results can also shed some light on reasons for the paradoxical results from clinical trials.

Trends in coronary heart disease--has the socio-economic differential changed?

OBJECTIVE: To compare both trends in rates of coronary heart disease and levels of coronary risk factors between different socio-economic groups. METHODS: Rates of coronary events for men and women aged 25 to 69 years were estimated from a population-based register in the Lower Hunter Region of New South Wales from 1985 to 1993. Risk factor levels were estimated for men and women aged 35 to 64 years from three surveys of risk factors conducted in 1983, 1988/89 and 1994 in the same study population. RESULTS: There was a decline in major coronary events from 1985 to 1993. The greatest decline was for fatal coronary events, which fell by between 4.3% and 9.1% per year. Trends in event rates were similar for all socio-economic groups, except for trends in non-fatal definite myocardial infarction among women. Women from the areas with high socio-economic status tended to have a greater reduction in non-fatal definite myocardial infarction compared with women from low socio-economic areas. Trends in risk-factor levels were similar except the prevalence of cigarette smoking among women from the lowest quintile of socio-economic status did not decline. CONCLUSION: Prevention strategies seem to have had a beneficial impact on this population, resulting in similar declines in rates of coronary events for all socio-economic groups. However, event rates are still high, suggesting a further reduction in mortality and morbidity is possible. This could be achieved by further reductions in smoking, cholesterol and blood pressure, especially among people from areas with low socio-economic status.

Constipation in Australian women: prevalence and associated factors.

A postal health survey was completed by 14761 young women (aged 18-23 years), 14070 middle-aged women (45-50 years) and 12893 older women (70-75 years). The prevalence of constipation was 14.1% (CI 13.5-14.7) in young women, 26.6% (CI 25.9-27.4) in middle-aged women, and 27% (CI 26.9-28.5) in the older women. The prevalence of hemorrhoids was 3.2% (CI 2.9-3.4 young), 17.7% (CI 17.1-18.4 middle-aged) and 18.3% (CI 17.6-19.0 older). In the middle-aged and older women, those who reported previous gynecologic surgery were between 18% and 63% more likely to report constipation; in the younger cohort, women with one or two children were also more likely to report constipation (adjusted OR 1.43-1.46). One-third of the young women and half the middle-aged and older women had sought help for constipation; the majority indicated that they were satisfied with the help available to them.

Changing patterns of coronary heart disease in the hunter region of New South Wales, Australia.

A population-based observational study of men and women aged 35-69 years in the Hunter Region of New South Wales, Australia, was conducted to assess the impact of risk-factor modification and increased drug therapy on the trends in major coronary events and case fatality. From 1985 to 1993, there were 3006 coronary deaths and 6450 nonfatal major coronary events. Rates of death and nonfatal myocardial infarction declined, but there was an increase in hospital admissions for prolonged chest pain. Reductions in cigarette smoking, diastolic blood pressure, total cholesterol, and increased use of aspirin can fully explain the 3.3% (95% confidence interval [CI] 2.4, 4.2) average annual reduction in rates of major coronary events for men and the 4.1% (95% CI 2.7, 5.5) reduction for women. In contrast, increased use of aspirin, beta-blockers, fibrinolytic therapy, and angiotensin-converting enzyme inhibitors explain less than half of the 8.9% (95% CI 5.9, 11.8) and 6.9% (95% CI 2.7, 10.9) average annual reduction in case fatality in hospital for men and women, respectively. These trends suggest a decline in severity of coronary heart disease consistent with reductions in risk-factor levels and improved acute medical treatment.

Reducing coronary heart disease in the Australian Coalfields: evaluation of a 10-year community intervention.

Coronary heart disease is a leading cause of death in Australia with the Coalfields district of New South Wales having one of the country's highest rates. Identification of the Coalfields epidemic in the 1970's led to the formation of a community awareness program in the late 1980's (the healthy heart support group) followed by a more intense community action program in 1990, the Coalfields Healthy Heartbeat (CHHB). CHHB is a coalition of community members, local government officers, health workers and University researchers. We evaluate the CHHB program, examining both the nature and sustainability of heart health activities undertaken, as well as trends in risk factor levels and rates of coronary events in the Coalfields in comparison with nearby local government areas. Process data reveal difficulties mobilising the community as a whole; activities had to be selected for interested subgroups such as families of heart disease patients, school children, retired people and women concerned with family nutrition and body maintenance. Outcome data show a significantly larger reduction in case fatality for Coalfields men (although nonfatal heart attacks did not decline) while changes in risk factors levels were comparable with surrounding areas. We explain positive responses to the CHHB by schools, heart attack survivors and women interested in body maintenance in terms of the meaning these subgroups find in health promotion discourses based on their embodied experiences. When faced with a threat to one's identity, health discourse suddenly becomes meaningful along with the regimens for health improvement. General public disinterest in heart health promotion is examined in the context of historical patterns of outsiders criticising the lifestyle of miners, an orientation toward communal rather than individual responsibility for health (i.e. community 'owned' emergency services and hospitals) and anger about risks from environmental hazards imposed by industrialists.

Coronary events and exposure to environmental tobacco smoke: a case-control study from Australia and New Zealand.

OBJECTIVES: To estimate the relative risk of coronary heart disease (CHD) associated with exposure to environmental tobacco smoke (ETS). DESIGN: Population-based case-control study. SUBJECTS: Cases were 953 people identified in a population register of coronary events, and controls were 3189 participants in independent community-based risk factor prevalence surveys from the same study populations. SETTING: Newcastle, Australia and Auckland, New Zealand. MAIN OUTCOME MEASURES: Acute myocardial infarction or coronary death. RESULTS: After adjusting for the effects of age, education, history of heart disease, and body mass index, women had a statistically significant increased risk of a coronary event associated with exposure to ETS (relative risk (RR) = 1.99; 95% confidence interval (CI) = 1.40-2.81). There was little statistical evidence of increased risk found in men (RR = 1.02, 95% CI = 0.81-1.28). CONCLUSION: Our study found evidence for the adverse effects of exposure to ETS on risk of coronary heart disease among women, especially at home. For men the issue is unclear according to the data from our study. Additional studies with detailed information on possible confounders and adequate statistical power are needed. Most importantly, they should use methods for measuring exposure to ETS that are sufficiently accurate to permit the investigation of dose-response relationships.