Living arrangement choices of elderly singles: effects of income and disability.

Logit regression is used to explain living arrangement choice of elderly single individuals. The propensity to live independently is found to increase with income and decrease with disability; an interaction effect for females suggests that income may lessen the impact of disability on the propensity to seek shared living arrangements. Independent living is less likely for people who are not white, foreign-born males, those with at least one adult child, and those in States with higher living costs; and more likely for the ever-married and those in States with high per capita nursing home use. If home care services are preferentially allocated to disabled elderly who live alone, resources may flow to higher income individuals who have been able to maintain independent households.     

Determinants of low birth weight: methodological assessment and meta-analysis

43 determinants of low birth weight were analyzed from 895 published papers in the English and French literature from 1970-1984. The assessment was limited to singleton births of women living at sea level with no chronic illness; rare factors and complications of pregnancy were excluded. The 43 factors were categorized as genetic and constitutional, demographic and psychosocial, obstetric, nutritional, maternal morbidity during pregnancy, toxic exposure and antenatal care. The existence and magnitude of a causal effect on birth weight, gestational age, prematurity and intrauterine growth retardation were determined by a set of methodological standards. In developed countries, the most important factor was cigarette smoking, followed by nutrition and pre-pregnancy weight. In developing countries the major determinants were racial origin, nutrition, low pre-pregnancy weight, short maternal stature, and malaria. Pre-pregnancy weight, prior premature birth or miscarriage, diethylstilbestrol exposure and smoking were major determinants of gestational duration, but the majority of prematurity was unexplained in both developed and developing countries. There is a need for future research on the effect of maternal work, prenatal care, and certain vitamin and mineral deficiencies on intrauterine growth, and the effect of genital tract infection, prenatal care, maternal employment, stress and anxiety on prematurity.     

Immunization coverage surveys: methodological studies in Indonesia

A field study was conducted in rural and urban areas of Indonesia to quantify the relative costs of surveys using the standard Expanded Program on Immunization (EPI) methodology or using 7 randomly selected households within each cluster. Specifically, the objectives were: to assess whether immunization schedules were being adhered to in the study areas; to quantify the differences in survey time and cost for a rural and urban setting between the standard EPI survey method and the statistically rigorous approach, whereby 7 starting households were selected randomly within each cluster; and to assess the applicability of Lot Quality Assurance techniques as a managerial tool in immunization programs. The 2 areas of study were the Gianyar "kapupaten"(district) of Bali and the "timur"(east) municipality of Jakarta. In both places reliable population data were available from the 1980 census and, in Bali, these had been continually updated through regular reporting of births, deaths, and migrations. Gianyar district was chosen because it is rural, has a fairly good immunization reporting system, up-to-date household lists, and is logistically convenient. Both types of surveys. the standard EPI method and the SRS method in which a randomly selected starting household is used for each child, were conducted in each of the study areas during September and October 1986. Children's ages were calculated, in months, with respect to the 1st day of the survey. The age and the date of immunization of each child were then used to compute the age at immunization in months. In Gianyar, 207 children aged from 15 months to less than 24 months had their immunization status properly recorded using the EPI survey method; 209 children were successfully recorded by the SRS method. Using the EPI method, it was estimated that 75.4% of the children had received 8 immunizations. Use of the SRS method gave an estimate of 86.6%. In Jakarta, 207 children were properly surveyed by the epi method, with an overall complete immunization rate of 25.1%. The SRS method, which properly surveyed 209 children, gave a rate of 24.4%. The survey results show that the majority of the children were not vaccinated according to the national immunization schedule. Failure to follow the schedule also was independent of coverage levels. Individual clusters can be correctly classified according to their immunization level using Lot Quality Assurance methods.     

Calcium and weight: clinical studies

Data from six observational studies and three controlled trials in which calcium intake was the independent variable (and either bone mass or blood pressure the original outcome variable) have been reanalyzed to evaluate the effect of calcium intake on body weight and body fat. Analysis reveals a consistent effect of higher calcium intakes, expressed as lower body fat and/or body weight, and reduced weight gain at midlife. Similarly, studies relating nutrient intake to body composition report negative associations between calcium intake and body weight at midlife and between calcium and body fat accumulation during childhood. There is a fairly consistent effect size, with each 300 mg increment in regular calcium intake associated with approximately 1 kg less body fat in children and 2.5-3.0 kg lower body weight in adults. Taken together these data suggest that increasing calcium intake by the equivalent of two dairy servings per day could reduce the risk of overweight substantially, perhaps by as much as 70 percent.     

Comparing survey data on functional disability: the impact of some methodological differences.

STUDY OBJECTIVE: To examine the impact of some differences in survey methodology on the prevalence of functional disability in population based surveys of the elderly. DESIGN AND METHODS: Nine surveys of Dutch people aged 55 years and older were compared to investigate the differences in the methods of data collection (proxy questioning, yes/no; interview versus self administered questionnaire) and construction of the questionnaire (wording of introductory text, activities, and response categories). The effect of these differences on prevalences in three domains of functional disability--activities of daily living, mobility, and communication--were studied. Both univariate analyses and multivariate logistic regression were used to quantify the methodological influences. RESULTS: No effect of proxy questioning could be shown. Self administered questionnaires yielded higher prevalences of disability than interviewer administered questionnaire--in particular for mobility (odds ratio (OR) 1.4, 95% confidence interval (95% CI) 1.3, 1.6) and communication (OR = 1.7, 95% CI 1.5, 1.9), resulting in prevalence differences of 9 and 11 percentage points respectively. Seemingly minor differences in the structure and wording of the questionnaires resulted in major differences (up to 15.6 percentage points) in prevalence estimates of functional disability. These differences were associated with the severity level of the disability indicated by the wording of the questions. CONCLUSIONS: Differences in survey methodology have a substantial effect on the prevalence estimates of disability in the elderly. These differences should be taken into account when making international comparisons and studying time trends based on survey data.     

Cultural values and biomedical knowledge: choices in infant feeding. Analysis of a survey

This paper presents a study of 313 parturient women and considers their choices to bottle or breast feed. It examines demographic and cultural factors statistically and focuses on the effect of knowledge or ignorance of benefits of either method of infant feeding. Most women are found to have some biomedical knowledge of the benefits of breast feeding. The choice of bottle or breast feeding is closely associated with several demographic factors and a number of cultural ideas. Women who bottle feed see some of their dietary and other health related practices as barriers to breast feeding. It recommends that health practitioners who decide that individual women and/or their infants may benefit from breast feeding, should engage in a dialogue with the women. Such a dialogue should focus, not so much on information, but on the woman's views about her dietary and other health practices. If the woman is given compelling health reasons she may see herself as capable of changing some practices long enough to breast feed.     

Bias magnification in ecologic studies: a methodological investigation

Background  

As ecologic studies are often inexpensive to conduct, consideration of the magnitude and direction of ecologic biases may be useful in both study design and sensitivity analysis of results. This paper examines three types of ecologic bias: confounding by group, effect measure modification by group, and non-differential exposure misclassification.     

Obesity and cognitive decline in adults: Effect of methodological choices and confounding by age in a longitudinal study

Background and Objectives

Obesity has been associated with increased risk of cognitive impairment or dementia, but recent findings are contradictory, possibly due to methodological differences. The present study tries to clarify these inconsistencies by following the cognitive trajectories of individuals with obesity over 12 years and studying the effect of obesity status (obesity at baseline versus incident obesity at follow-up), chronicity, definition, potential confounding (e.g. age, cardiovascular factors), and non-linear associations.

Design

Longitudinal study with 12 years follow-up.

Setting

Community based.

Participants

1,807 cognitively healthy individuals (aged 24-83) from the Maastricht Aging Study (1992-2004).

Measurements

Memory, executive function and processing speed were assessed at baseline and at 6- and 12-year follow-up. Obesity was defined as having a body mass index (BMI) of ≥ 30.0 kg/m² or waist circumference (WC) of > 102 cm for men and > 88 cm for women.

Results

At baseline, 545 persons were obese (BMI: 329 (18%); WC: 494 (27%); both: 278 (15%). They showed faster decline in memory, executive function, and processing speed. Chronic obese showed less widespread impairment than those who regained normal weight. Associations across cognitive domains were weaker for obesity defined by BMI than for WC. At follow-up, 190 developed obesity, and they performed worse on executive function at baseline, but showed less decline compared with participants with normal weight. Yet, age-stratification and post-hoc analyses showed that most of these associations were confounded by age.

Conclusions

This study shows that the association between obesity and cognitive decline was confounded by the effect of age on rate of decline. Future studies should take this into account.

     

Modeling consumer choices of health plans: A comparison of two techniques

This paper has two objectives. First, we will describe how conjoint measurement, a multivariate marketing research technique, can be applied in health care marketing. Second, we will compare the validity of results from two conjoint measurement techniques—the full profile approach and the tradeoff approach.A convenience sample of 97 university students was used in the study. Fifty-two students supplied data by using the full profile approach. Each respondent provided a complete rank order of 26 profile cards which included the following ambulatory health service attributes: charge for routine visit, travel time, office hours, length of time needed to make an appointment, waiting time in physician's office, practice arrangement/freedom of physician choice, parking arrangements and type of hospital. A fractional factorial design was used to determine different attribute levels (e.g. charge for routine office visit could be set at $10, $20 or $30) for each card. Forty-five students performed ranking tasks for the trade-off approach to conjoint measurement. These respondents ranked 28 grids which represent all combinations of factors taken two at a time. From the data collected in the ranking tasks, utilities or part-worth values for each level of each attribute were estimated by using dummy variable regression. Relative importance of ambulatory service attributes was inferred from the range of utility values of the attributes. Three measures of validity were assessed—adherence of estimated utility scores to monotonic assumptions, plausability of importance rankings and comparative validity. The results from the full-profile approach satisfied all three criteria. In contrast, the tradeoff approach results satisfied the first two criteria, but its comparative validity was only marginal.Valid conjoint data can be used for: simulations of market responses to different health services configurations; market segmentation studies; and development of promotional efforts.     

药品价格比较的方法学问题及比较策略研究

文章从研究地点和数据来源的选择,药品样本的选择,比较价格的定义、计价单位和货币转换,价格比较的方法等四个方面分析了药品价格比较的方法学问题,并在此基础上提出了我国药品价格比较的研究策略。     

History of health studies around nuclear facilities: a methodological consideration

A brief historical review was made of low-level radiation studies for general populations living around nuclear facilities. In addition, technical and methodological problems were identified and discussed which often arise in all epidemiological studies designed to determine the possible health effects of low-level radiation released from nuclear facilities. Many of the studies reviewed were incomplete from the methodological standpoint; thus findings may be considered inconclusive. Some others presented an inadequate study design with contradictory results. Need for extremely large populations for prospective cancer studies was discussed, but accompanying ascertainment difficulties were also emphasized. More epidemiological studies are needed to provide adequate assessment of the potential health hazards of nuclear facilities.     

Health outcomes are about choices and values: an economic perspective on the health outcomes movement

The aim of the health outcomes movement is to reorientate health services so that the spotlight shines less on what is done and more on what is achieved. The health outcomes movement, thus far, has been most successful in addressing what appear to be technical questions relating to the measurement and analysis of health outcomes and in placing their routine use on the agenda of clinical practice and health services planning. If there is one lesson to be drawn from an economic perspective, however, it is that health outcomes are about values and not just technicalities. The need to make choices forces one to consider whether what is achieved is also what is most valued. The success of health service delivery, be it at a clinical, planning or systems level, must therefore be measured against agreed objectives. It follows that time must be taken to establish what patients and the community want from their health services and what each is prepared to give up to achieve its ends. Value judgements are unavoidable. The challenge lies not in measuring the outcomes of health interventions but in deciding what the objectives of the health system ought to be.