Vaccination Inequality in India, 2002-2013

INTRODUCTION

India's childhood vaccination coverage has increased amid the implementation of national health policies intended to improve immunization levels. However, there is a dearth of contemporary studies comparing state-level childhood vaccination rates across India's highly diverse states and territories. This study assesses SES-based inequalities in childhood vaccination by state for 2002-2013.

METHODS

National surveys from 2002 to 2004, 2007 to 2008, and 2012 to 2013 were used for analyses. Household SES was assessed using an asset index created through principal component analysis. Full vaccination comprised 1 dose bacille Calmette-Guerin, 3 doses diphtheria-pertussis-tetanus vaccine, 3 doses oral polio vaccine, and 1 dose measles-containing vaccine at age 12-60 months. Inequality analyses were stratified by 3 time periods and by government-designated high focus group versus non-high focus group states.

RESULTS

Childhood vaccination steadily increased between 2002 and 2013 in high focus group states but fell in some non-high focus group states, whereas SES-based vaccination inequalities generally decreased in both. In 2012-2013, rural areas had lower vaccination rates than urban areas in high focus group states but similar vaccination rates as urban areas in non-high focus group states. Increases in vaccination rates were not consistently accompanied by improvements in SES-based inequalities in vaccination.

CONCLUSIONS

Childhood vaccination in India has improved overall, although increases are more pronounced in high focus group states than in non-high focus group states over the study period. The gap in coverage between these states decreased over time owing in part to the latter experiencing reductions in full vaccination rates during 2007-2013. SES-based vaccination disparities persist in India, highlighting the need to improve vaccination rates for all children, especially those from disadvantaged and underserved groups.

SUPPLEMENT INFORMATION

This article is part of a supplement entitled Global Vaccination Equity, which is sponsored by the Global Institute for Vaccine Equity at the University of Michigan School of Public Health.

Perceptions of alcohol-impaired driving and the blood alcohol concentration standard in the United States

INTRODUCTION

Although the number of alcohol-impaired driving (AID) fatalities has declined over the past several years, AID continues to be a serious public health problem. The purpose of this effort was to gain a better understanding of the U.S. driving population's perceptions and thoughts about the impacts of lowering the blood alcohol concentration (BAC) driving standard below.08% on AID, health, and other outcomes.

METHODS

A questionnaire was administered to a nationally representative sample of licensed drivers in the U.S. (n=1011) who were of age 21 or older on driving habits, alcohol consumption habits, drinking and driving habits, attitudes about drinking and driving, experiences with and opinions of drinking and driving laws, opinions about strategies to reduce drinking and driving, general concerns about traffic safety issues, and demographics.

RESULTS

One-third of participants supported lowering the legal BAC standard, and participants rated a BAC standard of .05% to be moderately acceptable on average. 63.9% indicated that lowering 30 the BAC to .05% would have no effect on their decisions to drink and drive. Nearly 60% of respondents lacked accurate knowledge of their state's BAC standard.

CONCLUSIONS

Public support for lowering the BAC standard was moderate and was partially tied to beliefs about the impacts of a change in the BAC standard. The results suggest that an opportunity for better educating the driving population about existing AID policy and the implications for lowering the BAC level on traffic injury prevention.

PRACTICAL APPLICATIONS

The study results are useful for state traffic safety professionals and policy makers to have a better understanding of the public's perceptions of and thoughts about BAC standards. There is a clear need for more research into the effects of lowering the BAC standard on crashes, arrests, AID behavior, and alcohol-related behaviors.

Percentage and severity of periodontal diseases in Turkish adults aged 35+ years, 2009-10

OBJECTIVE

This article presents data on the burden of periodontal diseases in Turkish adults aged 35 years or older.

METHODS

Within each region of Turkey, a rural and an urban area or city were selected in 2009-10 using a probability proportional to size method. In the selected towns, local officials who were familiar with their communities assisted in recruiting subjects. Loss of Attachment (LOA) was measured at six sites around each tooth present in the mouth, excluding third molars. Additionally, the Community Periodontal Index was used to assess the severity of periodontal diseases around 12 index teeth. Self-reported data on key risk factors were also collected. Weights were computed using a raking ratio adjustment procedure and used in all analyses.

RESULTS

Almost all examined adults had some loss of periodontal attachment. The proportion of those with more than 3 mm LOA ranged from 43 percent in 35-44 year olds to 91 percent in those aged 65+ years. Among females, older age, low education status, smoking 11-40+ cigarettes a day, being employed, and presence of high number of missing tooth surfaces were associated with LOA > 3 mm. Among males LOA >3 mm was associated with older age, use of alcohol, and unemployment. The CPI data did not yield the same associations with periodontal diseases and risk factors.

CONCLUSIONS

Periodontal diseases in Turkish adults are highly prevalent. A tailored common risk factor health promotion program is recommended to reduce the burden of periodontal infection in Turkey.

Predictors of vaccination in India for children aged 12-36 months

INTRODUCTION

India has one of the lowest immunization rates worldwide despite a longstanding Universal Immunization Program (UIP) that provides free childhood vaccines. This study characterizes the predictors for under- and non-vaccination among Indian children aged 12-36 months.

METHODS

This study utilized District Level Household and Facility Survey Data, 2008 (DLHS3), from India. DLHS3 is a nationally representative sample collected from December 2007 through December 2008; this analysis was conducted during 2014. Children's vaccination status was categorized as fully, under-, and non-vaccinated based on whether children received all, some, or none of the UIP-recommended vaccines (one dose each of bacillus Calmette-Guérin and measles, and three doses of diphtheria-pertussis-tetanus). A multinomial logistic regression model estimated the odds of undervaccination compared with full vaccination, and odds of non-vaccination compared with full vaccination. Analytic predictors included socioeconomic, cultural, household, maternal, and childhood characteristics.

RESULTS

The analysis included 108,057 children; the estimated proportions of fully, under-, and non-vaccinated children were 57%, 31%, and 12%, respectively. After adjusting for state of residence, age, gender, household wealth, and maternal education, additional significant predictors of children's vaccination status were religion, caste, place of delivery, number of antenatal care visits, and maternal tetanus vaccination, all of which demonstrated large effect sizes.

CONCLUSIONS

India's immunization coverage remained low in 2008, with just slightly more than half of all children aged 12-36 months fully vaccinated with UIP-recommended vaccines. A better understanding of the predictors for vaccination can help shape interventions to reduce disparities in full vaccination among children of differing demographic/cultural groups.

Predictors of Vaccination in India for Children Aged 12-36 Months

INTRODUCTION

India has one of the lowest immunization rates worldwide despite a longstanding Universal Immunization Program (UIP) that provides free childhood vaccines. This study characterizes the predictors for under- and non-vaccination among Indian children aged 12-36 months.

METHODS

This study utilized District Level Household and Facility Survey Data, 2008 (DLHS3), from India. DLHS3 is a nationally representative sample collected from December 2007 through December 2008; this analysis was conducted during 2014. Children's vaccination status was categorized as fully, under-, and non-vaccinated based on whether children received all, some, or none of the UIP-recommended vaccines (one dose each of bacillus Calmette-Guérin and measles, and three doses of diphtheria-pertussis-tetanus). A multinomial logistic regression model estimated the odds of under-vaccination compared with full vaccination, and odds of non-vaccination compared with full vaccination. Analytic predictors included socioeconomic, cultural, household, maternal, and childhood characteristics.

RESULTS

The analysis included 108,057 children; the estimated proportions of fully, under-, and non-vaccinated children were 57%, 31%, and 12%, respectively. After adjusting for state of residence, age, gender, household wealth, and maternal education, additional significant predictors of children's vaccination status were religion, caste, place of delivery, number of antenatal care visits, and maternal tetanus vaccination, all of which demonstrated large effect sizes.

CONCLUSIONS

India's immunization coverage remained low in 2008, with just slightly more than half of all children aged 12-36 months fully vaccinated with UIP-recommended vaccines. A better understanding of the predictors for vaccination can help shape interventions to reduce disparities in full vaccination among children of differing demographic/cultural groups.

Development of a psychosocial distress measure for Ugandan adolescents living with HIV

Psychological distress among adolescents living with HIV (ALH) has been associated with risky behaviors including non-adherence to anti-retroviral therapy, leading to increased risk for AIDS morbidity and mortality. Efforts to establish the nature, prevalence, and impact of psychological distress among ALH in Uganda are hindered by the lack of culturally relevant assessment tools. The purpose of this study was to develop and test a measure for psychological distress for Ugandan ALH aged 12-19 years (N = 508; 53.1 % female). Using a mixed method approach, we developed and tested a 25-item checklist with six subscales-anhedonia, depressive-anxiety, isolation, suicidal ideation, sleep problems, and somatization. We found adequate reliability for the scale (α = 0.89), and a satisfactory measurement structure in our confirmatory factor analyses (RMSEA <1.0, and CFI and TLI >0.90). We discuss the potential use of this culturally sensitive scale to examine psychological distress among ALH in Uganda.

Responsive Design, Weighting, andVariance Estimation in the 2006-2010 National Survey of Family Growth

Objective-The National Survey of Family Growth (NSFG) collects data on pregnancy, childbearing, men's and women's health, and parenting from a national sample of men and women aged 15-44 in the United States. The 2006-2010 NSFG design was a significant departure from the previous periodic design, used in 1973-2002. This report shows fieldwork results and weighting, imputation, and variance estimation procedures. The report should be useful to users of the 2006-2010 public-use data file and to survey methodologists wishing to learn how the NSFG was conducted. Methods-NSFG's new design is based on an independent national probability sample of men and women aged 15-44. The University of Michigan's Institute for Social Research conducted fieldwork under a contract with the National Center for Health Statistics. Professional female interviewers conducted in-person, face-to-face interviews using laptop computers. A responsive design approach was used in planning and managing the fieldwork for NSFG to control costs and reduce nonresponse bias. Results-The 2006-2010 NSFG is based on 22,682 completed interviews-10,403 interviews with men and 12,279 with women. Interviews with men lasted an average of 52 minutes, and for women, 71 minutes. Weighted response rates were 75% among men, 78% among women, and 77% overall. Analysis of NSFG data requires the use of sampling weights and estimation of sampling errors that account for the complex sample design and estimation features of the survey. Sampling weights are provided on the data files. The rate of missing data in the survey is generally low.

Estimation of age- and sex-specific background human serum concentrations of PCDDs, PCDFs, and PCBs in the UMDES and NHANES populations

Age- and sex-specific estimates of serum dioxin concentrations are important for comparisons among populations. However, such comparisons are problematic because populations have different age and sex structures and values are typically reported only in broad age ranges that are not comparable across studies. There are few studies that report congener-specific serum concentrations, and none that provide these by sex for age as a continuous function. We combined the NHANES 2003-2004 data with the University of Michigan Dioxin Exposure Study (UMDES) referent population 2005 data to achieve stable and accurate estimates of mean and quantiles of serum dioxins by sex over ages 18-85. Survey-weighted linear and quantile regression models were fitted on the combined data with the log-transformed congener concentration as outcome and age, sex, and data source as covariates. Formulas are provided to allow calculations of age- and sex-specific mean and quantile estimates over ages 18-85. For instance, the geometric mean, median, 75th percentile, and 95th percentile of serum TEQ for men aged 50 can be estimated, respectively, from the formulas as 18.33, 19.02, 22.60, and 30.37 pg g(-1) lipids among the Michigan general population, and as 15.71, 15.89, 22.60, and 29.90 pg g(-1) lipids among US non-Hispanic whites. These methods and results are useful for comparing the congener-specific human serum dioxin concentrations in any individual to the general population mean, median, 75th percentile, and 95th percentile, and for comparing the serum dioxin concentration in any group of interest to the US and the Michigan general populations.

Attitudes of pregnant women towards collection of biological specimens during pregnancy and at birth

Epidemiological investigations of maternal and child health may involve the collection of biological specimens, including cord blood and the placenta; however, the attitudes of pregnant women towards participation in the collection of biological specimens have been studied rarely. We evaluated attitudes towards collection and storage of biological specimens, and determined whether attitudes differed by maternal characteristics, in a cross-sectional study of pregnant women residing in Kent County, Michigan. Women were interviewed at their first visit for prenatal care between April and October 2006 (n = 311). Willingness to participate was highest for maternal blood collection (72%), followed by storage of biological specimens (68%), placenta collection (64%), and cord blood collection (63%). About one-quarter of women (25-28% by procedure) would not participate even if compensated. Hispanic ethnicity was associated with unwillingness to participate in maternal blood collection (OR = 2.16 [95% CI 1.15, 4.04]). Primiparity was associated with unwillingness to participate in cord blood collection (OR = 1.72 [95% CI 1.23, 2.42]). Among women willing to participate, Hispanic women were less likely to require compensation; while higher educated, married and primiparous women were more likely to require compensation. In conclusion, while many pregnant women were willing to participate in biological specimen collection, some women were more resistant, in particular Hispanic and primiparous women. Targeting these groups of women for enhanced recruitment efforts may improve overall participation rates and the representativeness of participants in future studies of maternal and child health.

Evaluation of a brief tailored motivational intervention to prevent early childhood caries

OBJECTIVES

This pragmatic randomized trial evaluated the effectiveness of a tailored educational intervention on oral health behaviors and new untreated carious lesions in low-income African-American children in Detroit, Michigan.

METHODS

Participating families were recruited in a longitudinal study of the determinants of dental caries in 1021 randomly selected children (0-5 years) and their caregivers. The families were examined at baseline in 2002-2004 (Wave I), 2004-2005 (Wave II) and 2007 (Wave III). Prior to Wave II, the families were randomized into two educational groups. An interviewer trained in applying motivational interviewing principles (MI) reviewed the dental examination findings with caregivers assigned to the intervention group (MI + DVD) and engaged the caregiver in a dialogue on the importance of and potential actions for improving the child's oral health. The interviewer and caregiver watched a special 15-minute DVD developed specifically for this project based on data collected at Wave I and focused on how the caregivers can 'keep their children free from tooth decay'. After the MI session, the caregivers developed their own preventive goals. Some families in this group chose not to develop goals and were offered the project-developed goals. The goals, if defined, were printed on glossy paper that included the child's photograph. Families in the second group (DVD-only) were met by an interviewer, shown the DVD, and provided with the project's recommended goals. Both groups of families received a copy of the DVD. Families in the MI + DVD group received booster calls within 6 months of the intervention. Both caregivers and the children were interviewed and examined after approximately 2 years (Wave III: 2007).

RESULTS

After 6-month of follow-up, caregivers receiving MI + DVD were more likely to report checking the child for 'precavities' and making sure the child brushes at bedtime. Evaluation of the final outcomes approximately 2 years later found that caregivers receiving the MI + DVD were still more likely to report making sure the child brushed at bedtime, yet were no more likely to make sure the child brushed twice per day. Despite differences in one of the reported behaviors, children whose caregivers received the motivational intervention did not have fewer new untreated lesions at the final evaluation.

CONCLUSIONS

This study found that a single motivational interviewing intervention may change some reported oral health behaviors, it failed to reduce the number of new untreated carious lesions.

The 2006-2010 National Survey of Family Growth: sample design and analysis of a continuous survey

OBJECTIVE

The National Survey of Family Growth (NSFG) collects data on pregnancy, childbearing, men's and women's health, and parenting from a national sample of women and men 15-44 years of age in the United States. This report describes the sample design for the NSFG's new continuous design and the effects of that design on weighting and variance estimation procedures. A working knowledge of this information is important for researchers who wish to use the data. Two data files are being released--the first covering 2.5 years (30 months) of data collection and the second after all data have been collected. This report is being released with the first data file. A later report in this Series will include specific results of the weighting, imputation, and variance estimation.

METHODS

The NSFG's new design is based on an independent, national probability sample of women and men 15-44 years of age. Fieldwork was carried out by the University of Michigan's Institute for Social Research (ISR) under a contract with the National Center for Health Statistics (NCHS). In-person, face-to-face interviews were conducted by professional female interviewers using laptop computers.

RESULTS

Analysis of NSFG data requires the use of sampling weights and estimation of sampling errors that account for the complex sample design and estimation features of the survey. Sampling weights are provided on the data files. The rate of missing data in the survey is generally low. However, missing data were imputed for about 600 key variables (called "recodes") that are used for most analyses of the survey. Imputation was accomplished using a multiple regression procedure with software called IVEware, available from the University of Michigan website.

Healthy aging in neighborhoods of diversity across the life span (HANDLS): overcoming barriers to implementing a longitudinal, epidemiologic, urban study of health, race, and socioeconomic status

OBJECTIVE

Examine the influences of race, socioeconomic status, sex, and age on barriers to participation in a study of cross-sectional differences and longitudinal changes in health-related outcomes.

METHODS

We designed a multidisciplinary, community-based, prospective longitudinal epidemiologic study among socioeconomically diverse African Americans and Whites. We recruited 3722 participants from Baltimore, Md. with a mean age of 47.7 (range 30-64) years, 45% males; 2200 African Americans (59%) and 1522 whites (41%); 41% reported household incomes below the 125% poverty delimiter.

RESULTS

There were no significant age differences associated with sex or race. Participants below the 125% poverty delimiter were slightly younger than those above the delimiter. Age, race, and sex, but not poverty status, were associated with the likelihood of a physical examination. Older participants, women, and Whites were more likely to complete their examinations. Among those who completed their examinations, there were no age differences associated with sex and poverty status, but African Americans were negligibly younger than Whites.

CONCLUSIONS

Although some literature suggests that minorities and low-income people are less willing to participate in clinical research, these baseline data suggest that African Americans individuals and individuals from households with incomes below 125% of the poverty level are at least as willing to participate in observational clinical studies as Whites and higher income individuals of similar age and sex.

Planning and development of the continuous National Survey of Family Growth

OBJECTIVES

This report describes how the continuous National Survey of Family Growth (NSFG) (begun in 2006) was designed, planned, and implemented. The NSFG is a continuous national survey of men and women 15-44 years of age designed to provide national estimates of factors affecting pregnancy and birth rates; men's and women's health; and parenting.

METHODS

The survey used in-person, face-to-face interviews conducted by trained female interviewers. One person per household was interviewed from a national area probability sample. The data collection used computer-assisted personal interviewing (CAPI). Separate questionnaires were used for male and female respondents. The last section of the questionnaires used a self-administered technique called audio computer-assisted self-interviewing or ACASI. Each data collection period lasted 12 weeks-10 weeks for "Phase 1," the main data collection protocol, and 2 weeks for "Phase 2," an intensive attempt to locate and interview nonrespondents.

RESULTS

Each year, about 5,000 persons were interviewed in about 33 areas, called primary sampling units (PSUs). Over a 4-year period, 110 PSUs will be used. This report gives an overview of the procedures used in the conduct of the continuous NSFG. A later report will describe response rates and other results of the data collection, but the early fieldwork has gone well.

Attitudes of pregnant women towards participation in perinatal epidemiological research

We assessed attitudes of a multi-ethnic sample of pregnant women in regard to participation in five data collection procedures planned for use in the National Children's Study. A cross-sectional survey was conducted in nine prenatal clinics in Kent County, Michigan between April and October 2006. Women were approached in clinic waiting rooms at the time of their first prenatal visit and 311 (91.0%) participated. Women were asked about their willingness to participate, and the smallest amount of compensation required for participation in a 45-min in-person interview, a 15-min telephone interview, maternal and infant medical record abstraction, and an infant physical examination. Percentages for willingness to participate were highest for telephone interview (83%), followed by in-person interview (60%), infant examination (57%), and maternal (56%) and infant medical records (54%). About 34-48% of women reported that no compensation would be required for participation by data procedure. Some women reported unwillingness to participate in telephone (9%) or personal (17%) interview, record abstraction (34%) or infant examination (26%), even with compensation. Education greater than high school was associated with increased odds of refusal for infant physical examination, adjusted odds ratio 2.44 [95% confidence interval 1.41, 4.23]. In conclusion, 9-34% of pregnant women, depending on procedure, stated they would not participate in non-invasive research procedures such as medical record abstraction and infant examination, even with compensation. Resistance to these research procedures was especially noted among more highly educated women. Planning for the National Children's Study will have to address potential resistance to research among pregnant women.

Obesity and sugar-sweetened beverages in African-American preschool children: a longitudinal study

A representative sample of 365 low-income African-American preschool children aged 3-5 years was studied to determine the association between sugar-sweetened beverage consumption (soda, fruit drinks, and both combined) and overweight and obesity. Children were examined at a dental clinic in 2002-2003 and again after 2 years. Dietary information was collected using the Block Kids Food Frequency Questionnaire. A BMI score was computed from recorded height and weight. Overweight and obesity were defined by national reference age-sex specific BMI: those with an age-sex specific BMI>or=85th, but <95th percentile as overweight and those with BMI>or=95th age-sex specific percentile as obese. The prevalence of overweight was 12.9% in baseline, and increased to 18.7% after 2 years. The prevalence of obesity increased from 10.3 to 20.4% during the same period. Baseline intake of soda and all sugar-sweetened beverages were positively associated with baseline BMI z-scores. After adjusting for covariates, additional intake of fruit drinks and all sugar-sweetened beverages at baseline showed significantly higher odds of incidence of overweight over 2 years. Among a longitudinal cohort of African-American preschool children, high consumption of sugar-sweetened beverages was significantly associated with an increased risk for obesity.

Estimation of the proportion of overweight individuals in small areas - a robust extension of the Fay-Herriot model

Hierarchical model such as Fay-Herriot (FH) model is often used in small area estimation. The method might perform well overall but is vulnerable to outliers. We propose a robust extension of the FH model by assuming the area random effects follow a t distribution with an unknown degrees-of-freedom parameter. The inferences are constructed using a Bayesian framework. Monte Carlo Markov Chain (MCMC) such as Gibbs sampling and Metropolis-Hastings acceptance and rejection algorithms are used to obtain the joint posterior distribution of model parameters. The procedure is used to estimate the county-level proportion of overweight individuals from the 2003 public-use Behavioral Risk Factor Surveillance System (BRFSS) data. We also discuss two approaches for identifying outliers in the context of this application.

National Survey of Family Growth, Cycle 6: sample design, weighting, imputation, and variance estimation

OBJECTIVES

Cycle 6 of the National Survey of Family Growth (NSFG) was conducted by the National Center for Health Statistics in 2002 and early 2003. This report describes how the sample was designed, shows response rates for various subgroups of men and women, describes how the sample weights were computed to make national estimates possible, shows how missing data were imputed for a limited set of key variables, and describes the proper ways to estimate sampling errors from the NSFG. The report includes both nontechnical summaries for readers who need only general information and more technical detail for readers who need an in-depth understanding of these topics.

METHODS

The NSFG Cycle 6 was based on an independent, national probability sample of men and women 15-44 years of age. It was the first NSFG ever to include a national sample of men 15-44 as well as a sample of women. Fieldwork was carried out by the University of Michigan's Institute for Social Research (ISR) under a contract with NCHS. In-person, face-to-face interviews were conducted by professional female interviewers using laptop computers. In all, 12,571 women and men-7,643 females and 4,928 males-were interviewed, the largest NSFG ever done.

RESULTS

Analysis of NSFG Cycle 6 data requires the use of sampling weights and estimation of sampling errors that accounts for the complex sample design and estimation features of the survey. Examples of how to use several available software packages that incorporate complex design features in estimation, such as SAS, SUDAAN, and STATA, are presented.

Characteristics of sexual partners and STD infection among American adolescents

Adolescents are a high risk group for HIV infection and the characteristics of their partners may affect their susceptibility to infection. The goal of this study was to examine the effects of partner characteristics on sexually transmitted disease (STD) infection in a national sample of adolescents. Data from 8,024 sexually active adolescents who participated in the National Longitudinal Study of Adolescent Health (Add Health) in the United States were included in this study. Logistic models were used to examine the association of partner characteristics including age, neighbourhood, ethnicity, and school attendance on the self-report history of STD infection. The partner characteristics of age and school attendance were associated with the reporting of STD infection. The odds ratio for STD infection was 1.46 (95% confidence interval (CI) (1.22-1.75), P < 0.01) if the adolescent's partner was two or more years older and 1.37 (95% CI (1.16-1.62), P < 0.01) if the partner did not attend the adolescent's school. The odds ratios for having an older partner were also significant and positive for eight different STDs. Partner characteristics were associated with STD infection among American adolescents. Counselling is needed in clinics that serve adolescents to raise awareness of the risk of infection in these relationships and to improve skills in condom negotiation and use.

Willingness to pay for dentin regeneration in a sample of dentate adults

OBJECTIVES

Measurement of individuals' valuation of dental treatments is important in the evaluation of new technologies. In this paper the value of dentin regeneration, a new treatment for teeth with reversible pulpitis, is measured based on what individuals say they would be willing to pay to receive the treatment.

METHODS

A total of 611 randomly selected dentate adults answered willingness to pay (WTP) and dental insurance questions. Detailed descriptions of the process and expected outcomes for dentin regeneration were presented to subjects as part of a larger study measuring preferences for different treatments. WTP was determined for two different levels of success for dentin regeneration.

RESULTS

At a success rate of 95%, the mean WTP for dentin regeneration was $262.70 (noninsured) and $11.00 per month (insured subjects). For success rate of 75%, the corresponding values were $210.90 and $9.20 per month. Multivariate analyses were used to identify any significant relationships between WTP and a range of variables covering socio-demographic, socio-economic, dental experience and oral health status variables. The findings indicate that individuals' valuations of treatments involve substantial unexplained variation. About half of the noninsured subjects would pay for dentin regeneration if it cost $200 per tooth.

CONCLUSIONS

The data on the WTP for dentin regeneration indicate that a substantial percentage of adults will pay for this new technology. This study provides for the first time an estimate of WTP for dentin regeneration among the population.

Utilities of dentin regeneration among insured and uninsured adults

OBJECTIVES

This population-based study measured utilities (preferences measured under conditions of uncertainty) of dentin regeneration (DR), a potential new therapy, root canal therapy (RCT), and extraction (EXT).

METHODS

A representative sample of dentate adults (aged 18-69 years) was randomly selected from the Detroit area. A computer program was used to administer the standard gamble (SG) method and record utility score (US) for treatment options of a tooth with reversible pulpitis using the SG method. For the SG method, two anchor states were used: filled tooth with full oral health and filled tooth with severe and continuous pain leading to EXT. Additional data were obtained using a self-administered questionnaire.

RESULTS

Out of the 807 adults who resided in 446 screened and selected households, a final sample of 630 adults who resided in 368 households were interviewed. The mean US for DR with 75 and 95% success rates were 72.5 and 86.2 (on a 0-100 scale), respectively. The US for RCT and immediate EXT were 75.6 and 31.3, respectively. Eleven per cent of the adults valued DR with 95% success probability higher than a simple filling with full oral health for life. There were no statistically significant differences in the average US of DR between insured and uninsured adults. Factors such as gender, race, education, income and insurance status, experiences with EXTs or root canal treatment, regularity of dental visits, quality of life, and quality of oral health were not significantly associated with the scores of DR. There was, however, a small but significant interaction between race and dental insurance, and race and gender.

CONCLUSION

This population-based study found that DR was highly preferred to other standard treatment options.

Ethnicity or race, area characteristics, and sexual partner choice among American adolescents

The aim of this paper is to examine the association of individual demographic variables and area characteristics with the characteristics of sexual partners of American adolescents. Data for the study were drawn from the National Longitudinal Study of Adolescent Health. The data indicate that the community characteristics of ethnic or racial composition of the population and region were most strongly related to the ethnicity or race of the partner. Regional differences in the ethnicity or race of partners were significant even after controlling for the ethnic or racial composition of the community. Differences in partner s age, grade, neighborhood, and school or residence were not related to school and community characteristics. In addition, the individual characteristics of age, gender, and race or ethnicity were also related to ethnicity or race of partner.

Socioeconomic disparities in health change in a longitudinal study of US adults: the role of health-risk behaviors

This study investigated the hypothesis that socioeconomic differences in health status change can largely be explained by the higher prevalence of individual health-risk behaviors among those of lower socioeconomic position. Data were from the Americans' Changing Lives study, a longitudinal survey of 3,617 adults representative of the US non-institutionalized population in 1986. The authors examined associations between income and education in 1986, and physical functioning and self-rated health in 1994, adjusted for baseline health status, using a multinomial logistic regression framework that considered mortality and survey nonresponse as competing risks. Covariates included age, sex, race, cigarette smoking, alcohol consumption, physical activity, and Body Mass Index. Both income and education were strong predictors of poor health outcomes. The four health-risk behaviors under study statistically explained only a modest portion of the socioeconomic differences in health at follow-up. For example, after adjustment for baseline health status, those in the lowest income group at baseline had odds of moderate/severe functional impairment in 1994 of 2.11 (95% C.I.: 1.40, 3.20) in an unadjusted model and 1.89 (95% C.I.: 1.23, 2.89) in a model adjusted for health-risk behaviors. The results suggest that the higher prevalence of major health-risk behaviors among those in lower socioeconomic strata is not the dominant mediating mechanism that can explain socioeconomic disparities in health status among US adults.

Excess mortality among urban residents: how much, for whom, and why?

OBJECTIVES

The goals of this study were to estimate prospective mortality risks of city residence, specify how these risks vary by population subgroup, and explore possible explanations.

METHODS

Data were derived from a probability sample of 3617 adults in the coterminous United States and analyzed via cross-tabular and Cox proportional hazards methods.

RESULTS

After adjustment for baseline sociodemographic and health variables, city residents had a mortality hazard rate ratio of 1.62 (95% confidence interval [CI] = 1.21, 2.18) relative to rural/small-town residents; suburbanites had an intermediate but not significantly elevated hazard rate ratio. This urban mortality risk was significant among men (hazard rate ratio: 2.25), especially non-Black men, but not among women. Among Black men, and to some degree Black women, suburban residence carried the greatest risk. All risks were most evident for those younger than 65 years.

CONCLUSIONS

The mortality risk of city residence, at least among men, rivals that of major psychosocial risk factors such as race, low income, smoking, and social isolation and merits comparable attention in research and policy.

Socioeconomic factors, health behaviors, and mortality: results from a nationally representative prospective study of US adults

CONTEXT

A prominent hypothesis regarding social inequalities in mortality is that the elevated risk among the socioeconomically disadvantaged is largely due to the higher prevalence of health risk behaviors among those with lower levels of education and income.

OBJECTIVE

To investigate the degree to which 4 behavioral risk factors (cigarette smoking, alcohol drinking, sedentary lifestyle, and relative body weight) explain the observed association between socioeconomic characteristics and all-cause mortality.

DESIGN

Longitudinal survey study investigating the impact of education, income, and health behaviors on the risk of dying within the next 7.5 years.

PARTICIPANTS

A nationally representative sample of 3617 adult women and men participating in the Americans' Changing Lives survey.

MAIN OUTCOME MEASURE

All-cause mortality verified through the National Death Index and death certificate reviews.

RESULTS

Educational differences in mortality were explained in full by the strong association between education and income. Controlling for age, sex, race, urbanicity, and education, the hazard rate ratio of mortality was 3.22 (95% confidence interval [CI], 2.01-5.16) for those in the lowest-income group and 2.34 (95% CI, 1.49-3.67) for those in the middle-income group. When health risk behaviors were considered, the risk of dying was still significantly elevated for the lowest-income group (hazard rate ratio, 2.77; 95% CI, 1.74-4.42) and the middle-income group (hazard rate ratio, 2.14; 95% CI, 1.38-3.25).

CONCLUSION

Although reducing the prevalence of health risk behaviors in low-income populations is an important public health goal, socioeconomic differences in mortality are due to a wider array of factors and, therefore, would persist even with improved health behaviors among the disadvantaged.

Depression in black and white women. The role of marriage and socioeconomic status

The degree to which the relationship between race and depression in US black and white women is modified by socioeconomic and marital status was investigated. Data on 534 black and 836 white women, 25 to 64 years old, obtained from the 1986 Americans' Changing Lives national survey were utilized. Depression was measured by the Centers for Epidemiologic Studies Depression scale. Poverty status and education were used as indicators of socioeconomic status (SES). For both black and white women, the prevalence of depression was higher among those with lower as compared to higher SES, and among the unmarried as compared to the married. The unstratified, age-adjusted odds of depression for black women was twice that for white women (odds ratio (OR) = 2.2; 95% confidence interval (CI), 1.7 to 2.8); however, when stratified by poverty status, race effects were observed for nonpoor (OR = 2.2; 95% CI, 1.6 to 3.0) but not for poor women (OR = 1.3; 95% CI, 0.7 to 2.1). Race effects were also more pronounced among married (OR = 2.0; 95% CI, 1.4 to 2.9) than unmarried women (OR = 1.6; 95% CI, 1.1 to 2.4). Controlling for known confounders did not alter these results. Additional analyses revealed that the black excess risk for depression was concentrated among higher SES, married women, with marital difficulties appearing to pay a major role in their elevated depression scores.

The social stratification of aging and health

The way health varies with age is importantly stratified by socioeconomic status (SES)--specifically, education and income. Prior theory and cross-sectional data suggest that among higher SES persons the onset of health problems is usually postponed until rather late in life, while health declines are prevalent in lower SES groups by middle age. Thus, SES differences in health are small in early adulthood, but increase with age until relatively late in life, when they diminish due to selection or greater equalization of health risks and protections. The present paper strengthens our causal and interpretive understanding of these phenomena by showing: (1) that results previously reported for indices of SES hold separately for education and income; (2) that the interaction between age and SES (i.e., education or income) in predicting health can be substantially explained by the greater exposure of lower SES persons to a wide range of psychosocial risk factors to health, especially in middle and early old age, and, to a lesser degree, the greater impact of these risk factors on health with age; and (3) that results (1) and (2) generally hold in short-term longitudinal as well as in cross-sectional data. Implications for science and policy in the areas of aging, health, and social stratification are discussed.

The cost effectiveness of strategies to reduce barriers to cataract surgery. The Operations Research Group

The cost and effectiveness of eight approaches to reducing barriers to cataract surgery were evaluated in a rural area of South India during 1987-1989. The approaches were based on four intervention alternatives--aphakic motivator (AM), basic eye health worker (BW), screening van (SV), and mass media (MM). Each intervention was offered at two levels of economic incentive: partial, which provides free surgery and hospital stay, and full, which also provides transport from the recipient's village to the hospital and free food during the hospital stay. Evaluations took place in a probability selection of 90 villages, including ten control villages not subjected to either of the interventions. Only costs unique to patients from the intervention villages were considered: Health education and screening costs were included, surgery costs were not. Percentage reductions in the cataract blind backlog and increases in surgical coverage were used as effectiveness measures. Analyses suggest that the SV and AM interventions, both with full economic incentive, offer the greatest advantage. The AM intervention is the more effective of the two, but also the more costly.

Social determinants of cataract surgery utilization in south India. The Operations Research Group

A field trial was conducted to compare the effects of eight health education and economic incentive interventions on the awareness and acceptance of cataract surgery. Cataract screening and follow-up surgery were offered to more than 19,000 residents age 40 years and older in a probability sample of 90 villages in south India. Eight months after intervention, an evaluation was conducted to identify those in need of surgery who had been operated on. Two principal measures of program effectiveness are examined: awareness of cataract surgery and acceptance of the surgery. The type of intervention had a negligible effect on awareness of cataract surgery. A multiple logistic regression analysis revealed that individuals who were aware of surgery tended to be male, literate, and more affluent than those who were unaware of that option. Interventions that covered the complete costs of surgery had higher surgery acceptance rates. One health education strategy, house-to-house visits by a subject with aphakia, increased acceptance of the procedure more than others. In a multiple logistic regression analysis of acceptance rates, persons accepting surgery tended to be male; other factors were not important in explaining variation in acceptance rates.

Levels of disability among U.S. adults with arthritis

This article studies the excess levels of disability experienced by persons with arthritis, compared to persons without the disease. The data set is the Supplement on Aging (1984 National Health Interview Survey); it has information for a national probability sample of community-dwelling persons ages 55 + (N = 16,148). (1) Arthritis people have more difficulty in physical functions, personal care, and household care than do nonarthritis persons. The excess disability is greatest for physical functions (walking, reaching, stooping, etc.). Disabled arthritis people have especially high degrees of difficulty in physical activities that require endurance and strength. (2) Various models are tested for walking, grasping, shopping, and light housework to show how comorbidity propels disability for arthritis people and to show arthritis' own contribution to disability in the presence of other chronic conditions. Difficulties escalate for arthritis people when they have other concurrent conditions. These models affirm that arthritis has a pronounced effect on physical dysfunctions, but these are not readily translated into personal and household care problems. Apparently, arthritis people often make successful accommodations so their roles and daily activities are not seriously affected by the disease.

Sampling the difficult-to-sample

Difficult-to-sample populations are defined as rare populations or populations that are difficult to locate, enumerate or interview. This definition includes subgroups of the United States population that are at increased risk of adverse health effects associated with malnutrition. Examples include persons who are rare (pregnant women), difficult to locate (migrant farm workers), difficult to enumerate (homeless individuals) or difficult to interview (substance abusers). Probability methods to sample rare and elusive populations are reviewed briefly. Methods include disproportionately allocated sampling, multiplicity sampling and the use of multiple frames. The advantages and disadvantages of nonprobability sampling methods are compared using criteria typically applied to assess alternative probability sampling methods. The cost of data collection alone may prohibit consideration of probability sampling methods, but caution is urged before abandoning this statistically sound approach to sample selection. Considerations for sampling the difficult-to-sample are illustrated for one such population, the homeless.

Comorbidity and its impact on disability

Older people often suffer from comorbidity, or several chronic conditions simultaneously. Disability rises rapidly as the number of chronic conditions grows, although very ill people who acquire another condition experience attenuated increases. High prevalence conditions such as arthritis tend to have a low or occasionally moderate impact for community residents, while low prevalence ones such as osteoporosis have a high impact; paired conditions sometimes give extra propulsion to disability, as when cerebrovascular disease and hip fracture co-occur. Further research is needed to pin-point combinations of conditions posing great risks and to identify demographic segments in which comorbidity has elevated effects.

Health care utilization and costs of adult cardiovascular conditions United States, 1980

Cardiovascular conditions have a major economic as well as health impact on adults in the United States. In the National Medical Care Utilization and Expenditure Survey, conducted during 1980, health service data were obtained from a national sample of 17,123 civilian noninstitutionalized individuals. These data have been analyzed to define the impact and demographic patterns of health care utilization and costs attributable to adult cardiovascular conditions. Approximately 28 million persons in the United States, or 17.3 percent of the total civilian noninstitutionalized population 17 years of age and over, had a cardiovascular condition during 1980. Cardiovascular conditions were reported with increasing frequency in successively older age groups and were reported most frequently by black persons. The prevalence and economic impact differed by specific type of cardiovascular condition and whether the condition was complicated by another disease. To examine these differences, persons reporting cardiovascular conditions were categorized into four mutually exclusive groups: persons with hypertension alone, persons with arteriosclerotic cardiovascular and cerebrovascular disease associated with hypertension, persons with arteriosclerotic cardiovascular disease alone, and persons with cardiovascular disease associated with other conditions that might alter medical care utilization and disability. The disability, service utilization, and health care charges were compared among these groups, and data for each group were compared with those for the overall U.S. population. Survey participants were asked to rate their health relative to that of other people their age. The self-rating of persons reporting hypertension alone was lower than the national average. Only 17 percent of the general population rated their health as "fair" or "poor," but 27 percent of persons with hypertension alone used these descriptions. Overall, persons with hypertension alone were much less likely to be employed than the general population (52.2 percent versus 71.6 percent). However, when controlling for age, it was found that persons with hypertension alone were about as likely to be employed as the general population. On the average, persons with hypertension reported only slightly more work-loss days than did the general population (6.5 versus 4.9 days). A modest restriction of activity was reported by those with hypertension alone (20.1 days per year on the average compared with 15.6 for the general population). The mean number of ambulatory visits per year for those with hypertension alone was 7.9, only slightly greater than the 5.7 average for the overall population.(ABSTRACT TRUNCATED AT 400 WORDS)

Rapid epidemiologic assessment of cataract blindness. The Aravind Rapid Epidemiologic Assessment Staff

A major constraint to obtaining reliable information about blindness and its causes in developing countries is the limited availability of ophthalmologists for diagnosis in population-based surveys. This study in rural south India assessed the feasibility of using non-ophthalmologists to make diagnoses in a population-based survey. Ten men in their early twenties with 12 years of schooling were recruited and trained as ophthalmic assistants through a six week course in basic ophthalmology. All people aged 40 and older in households in 24 villages were enumerated and invited to have an eye examination. At a central site, 1309 subjects were independently examined by an ophthalmologist and two different ophthalmic assistants. Ophthalmic assistant cataract diagnosis is both sensitive and specific relative to the ophthalmologist's diagnosis. Sensitivity and specificity estimates were used to adjust prevalence estimates obtained from ophthalmic assistant examinations conducted at the central site as well as at the doorstep of sample households. The findings indicate that epidemiologic assessment of cataract blindness can be completed using non-ophthalmologists to diagnose cataract.

Strategies for the analysis of imputed data from a sample survey. The National Medical Care Utilization and Expenditure Survey

Missing data in sample surveys is virtually unavoidable, whether it is an entire unit that is missing or only an item for a responding unit. Compensation for unit nonresponse is usually made through the assignments of weights to responding units; for item nonresponse, the compensation often is by an imputation procedure. This paper reviews the extent of missing data in a large federal survey, the National Medical Care Utilization and Expenditure Survey, and the imputation procedures used to compensate for item missing data. The effects of imputation on several types of estimates from the survey are examined. In addition, several methods for analyzing survey data with imputed values are reviewed, and recommendations about preferred strategies are made for selected circumstances.

Disability, utilization, and costs associated with musculoskeletal conditions

In this report, data from the 1980 National Medical Care Utilization and Expenditure Survey are used to present health characteristics, types and quantities of services used, and the charges for these services for persons with musculoskeletal diseases. Slightly more than 44 million people, or 19.8 percent of the U.S. civilian noninstitutionalized population, were reported in the survey to have at least one musculoskeletal disorder. These data are generally consistent with those from other health surveys, which show that the prevalence of musculoskeletal disorders increases for successive age categories, that such disorders are more common among women than among men, and that they are less prevalent among black persons than among persons of other races. In terms of both functional limitation and perceived health status, persons with musculoskeletal conditions are, with some notable exceptions, in relatively poor health. Persons having back problems in addition to problems with peripheral joints (such as the knee, hip, or shoulder) were more likely to rate their health as "fair" or "poor" compared with persons having only back problems or compared with persons in the civilian noninstitutionalized population as a whole. Musculoskeletal disorders accounted for a considerable proportion of all disability days reported by the total civilian noninstitutionalized population: 13 percent of restricted-activity days, 8.8 percent of bed-disability days, and 11.2 percent of all work-loss days were directly attributable to musculoskeletal conditions. The disabling effects of musculoskeletal problems pose a significant economic burden; they accounted for a total of $3.9 billion in lost productivity costs during 1980 for employed persons in the work force and for homemakers. For persons with musculoskeletal problems, the mean number of ambulatory visits per year was nearly twice the rate of 5.2 for the general civilian noninstitutionalized population. Of ambulatory visits made to all health care providers by persons with these conditions, 35.6 percent were related in some way to the treatment of their musculoskeletal problems. Musculoskeletal conditions are somewhat different from many other illnesses because their treatment is within the professional domain of several types of health care providers. Approximately 13 percent of persons with any type of musculoskeletal disorder received care from chiropractors during the year and this figure rose to nearly 30 percent for back problems only. However, nearly 33 percent of persons with musculoskeletal problems made no visits for treatment of their condition.(ABSTRACT TRUNCATED AT 400 WORDS)

Incidence, utilization, and costs associated with acute respiratory conditions, United States, 1980

Acute respiratory conditions are common causes of health disturbance in the general population. They are generally self-limiting, although occasionally recurrent, and seldom result in large health care costs for each episode of illness. The National Medical Care Utilization and Expenditure Survey (NMCUES), conducted during 1980, provided an opportunity to assess the effect of acute respiratory conditions on utilization of medical services and on functional capability as well as the cost of related medical care. Acute respiratory conditions were reported by survey respondents and separated into five subgroups: colds, influenza, nasopharyngitis, otitis media, and lower respiratory infections. Allergic conditions and chronic respiratory disorders (tuberculosis, chronic obstructive pulmonary disease, and pneumoconioses) were excluded. The subgroupings of acute respiratory conditions appear to separate the disorders in a manner consistent with the epidemiologic characteristics of each condition. About one-half (50.4 percent) of the U.S. civilian noninstitutionalized population had one or more acute respiratory conditions during 1980. The highest rates for upper respiratory conditions (colds, influenza, nasopharyngitis, and otitis media) were reported for those under 18 years of age, and rates were lower in successively older groups. Lower respiratory infection rates were higher in the youngest and oldest groups. Despite a high incidence in the general population, most symptomatic episodes of colds, influenza, and nasopharyngitis did not result in ambulatory care visits or hospital admissions. Otitis media and lower respiratory infections were more often associated with medical visits. Acute respiratory conditions were associated with lower disability levels than the average for the U.S. civilian noninstitutionalized population during 1980 (5.9 restricted-activity days for acute respiratory conditions, compared with an overall average of 13.8 restricted-activity days). Persons with upper respiratory conditions (colds, influenza, otitis media, and nasopharyngitis) averaged 2.3 to 5.4 restricted-activity days, but persons with lower respiratory infections experienced an average of 8.2 restricted-activity days. Indirect costs attributed to acute respiratory conditions in 1980 were $7.7 billion for employed persons and $698 million for homemakers, for a total of $8.4 billion, about the same as total direct costs ($8.3 billion). These indirect costs were several times larger than the annual indirect costs estimated for either cardiovascular diseases or musculoskeletal diseases, two common chronic or recurrent condition groups. The high indirect costs reflect the high frequency of episodes in the general population during 1980 and the greater likelihood of associated bed-disability and work-loss days than for other conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Costs of illness: United States, 1980

The total costs of illness and injury in the U.S. civilian noninstitutionalized population in 1980 amounted to $381.7 billion. The direct costs of illness and injury--resource expenditures for the diagnosis, treatment, and management of medical and dental conditions--were $153.9 billion, or 40.3 percent of total costs. Indirect costs--economic losses from morbidity and mortality--were $227.9 billion, or 59.7 percent of total costs. Of indirect costs, $104.9 billion resulted from productivity losses because of morbidity, and $123.0 billion represent the present value of lost productivity from premature mortality based on a net effective discount rate of 4 percent. These estimates, based on data from the 1980. National Medical Care Utilization and Expenditure Survey (NMCUES), differ from other estimates of the costs of illness and injury in 1980 (Gibson and Waldo, 1982; Rice, Hodgson, and Kopstein, 1985). The differences, which can be resolved, are attributable to two major factors: (1) NMCUES includes only the civilian noninstitutionalized population, but the other estimates include the institutionalized population and the military; and (2) NMCUES indirect cost estimates for the population unable to work include persons who were retired for health reasons in 1979 and 1980, disabled homemakers, and other persons who were disabled for the entire year 1980 but were not retired for health reasons in 1979, but the Rice et al. estimates do not include the last two categories in the population unable to work. The principal NMCUES findings on the total costs of illness in the civilian noninstitutionalized population reinforce the importance of considering distributional effects. Persons 65 years of age and over represent one-tenth of this population yet account for more than one-fourth of direct costs and more than their share of total costs, even though the institutionalized elderly are excluded. More than two-thirds of total costs for this age category are accounted for by direct costs. Direct costs also account for more than two-thirds of total costs for people under 17 years of age. However, this youngest age category, which constitutes over one-fourth of the civilian noninstitutionalized population, generates only 12.3 percent of direct costs. In contrast, indirect costs account for well more than 60 percent of total costs for the working-age population (17-64 years of age). Within the working-age population, per capita direct costs are highest among persons who are not full participants in the work force, many of whom are not working full time or at all because of injury or ill health.(ABSTRACT TRUNCATED AT 400 WORDS)

Epidemiology of blindness in Nepal

This report presents the major findings of the Nepal Blindness Survey, the first nationwide epidemiological survey of blindness, which was conducted in 1979-80. The survey was designed to gather data that could be used to estimate the prevalence and causes of blindness in the country. Ancillary studies were conducted to obtain information on socioeconomic correlates and other risk factors of blinding conditions and patterns of health care utilization.The nationwide blindness prevalence rate is 0.84%. Cataract is the leading cause of blindness, accounting for over 80% of all avoidable blindness. Trachoma is the most prevalent blinding condition, affecting 6.5% of the population. Very few cases of childhood blindness were detected.The implications of the survey findings for programme planning, health manpower development, and health education are discussed.

Reliability of ophthalmic diagnoses in an epidemiologic survey

In the Nepal Blindness Survey, 39,887 people in 105 sites were examined by 10 ophthalmologists from Nepal and four other countries during 1981. Ophthalmic protocols were pretested on approximately 3000 subjects; however, interobserver variability was inevitable. To quantify the amount of variability and assess the reliability of important ophthalmic measures, a study of interobserver agreement was conducted. Five ophthalmologists, randomly assigned to one of two examining stations in a single survey site, carried out 529 pairs of examinations. Eighty demographic and ophthalmic variables were assessed at each station. In 62 of 80 (77.5%) measures, observer agreement exceeded 90%. Since pathologic findings were rare, however, chance agreement alone could yield misleadingly high per cent agreement; therefore, the kappa statistic was used for assessing comparative reliability of ophthalmic measures. There were 74 measures for which kappa could be computed and ranked by strength of agreement: 20 (27%) showed excellent agreement (kappa = 0.75-1.00), 39 (53%) showed fair to good agreement (kappa = 0.40-0.74), and 15 (20%) showed poor agreement (kappa less than 0.40). In general, measures dealing with blindness prevalence or causes of blindness showed substantial or almost perfect agreement, while polychotomous descriptions of rare clinical signs demonstrated less agreement.

Associations among cataract prevalence, sunlight hours, and altitude in the Himalayas

The relationship between cataract prevalence, altitude, and sunlight hours was investigated in a large national probability sample survey of 105 sites in the Himalayan kingdom of Nepal, December 1980 through April 1981. Cataract of senile or unknown etiology was diagnosed by ophthalmologists in 873 of 30,565 full-time life-long residents of survey sites. Simultaneously, the altitude of sites was measured using a standard mountain altimeter. Seasonally adjusted average daily duration of sunlight exposure for each site was calculated by a method which took into account latitude and obstructions along the skyline. Age- and sex-standardized cataract prevalence was 2.7 times higher in sites at an altitude of 185 meters or less than in sites over 1000 meters. Cataract prevalence was negatively correlated with altitude (r = -0.533, p less than 0.0001). However, a positive correlation between cataract prevalence and sunlight was observed (r = 0.563, p less than 0.0001). Sites with an average of 12 hours of sunlight exposure had 3.8 times as much cataract as sites with an average of only seven hours of exposure. Sunlight was blocked from reaching certain high altitude sites by tall neighboring mountains.