Namvar Zohoori

Monitoring the economic transition in the Russian Federation and its implications for the demographic crisis--the Russian Longitudinal Monitoring Survey.

Abstract Using data from the Russia Longitudinal Monitoring Survey, we provide information regarding changes in individual and household economic indicators, as well as alcohol consumption and nutritional status in Russia during 1992–1996. During this period, there have been declines in income and expenditure, and substantial increases in the prevalence of poverty. At the same time, per capita alcohol consumption has risen significantly, as has the prevalence of obesity. We discuss the significance of these findings within the context of the current mortality crisis in Russia.

Econometric approaches to epidemiologic data: Relating endogeneity and unobserved heterogeneity to confounding

The concepts of endogeneity and unobserved heterogeneity are well-known among econometricians. However, these issues are rarely addressed in epidemiologic studies. This paper explores these two concepts, their relationship to each other, and the implications for analysis in epidemiologic studies. An endogenous variable is defined as a predictor variable which is partly determined by factors within the model itself, while unobserved heterogeneity is conceptualized as a vector of missing variables acting through the error term. Under certain assumptions, the simultaneous existence of an endogenous variable and unobserved heterogeneity is shown to act in a manner analogous to confounding. Specifically, this occurs due to an association between the error term in the equation and the endogenous predictor variable. The accepted econometric solution to this problem is to replace the endogenous variable with an instrumental variable which is not correlated with the error term and thus not susceptible to confounding. The validity of these concepts and of the proposed solution are discussed.

Does WIC participation improve breast-feeding practices?

The effects of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on breast-feeding behavior have been sometimes found inadequate. The determinants of breast-feeding initiation and duration among WIC participants and nonparticipants were modeled by using retrospective cross-sectional data from the 1988 National Maternal and Infant Health Survey. This study corrects for self-selection bias as far as the data allow, in addition to controlling for parents ages, education, race, and family income. Findings suggest that prenatal WIC participation, combined with breast-feeding advice, significantly increases the initiation of breast-feeding but does not affect duration. The exact nature of effective breast-feeding advice given prenatally at WIC clinics is unclear and warrants further research.

Breast-feeding patterns in the Philippines: a prospective analysis

Data from the Cebu Longitudinal Health and Nutrition Survey have been used to examine breast-feeding patterns in the Metropolitan Cebu region of the Philippines. The results show that there is extensive and early use of non-nutritive liquids, resulting in low levels of exclusive breast-feeding. The use of cross-sectional versus longitudinal data, the definition of exclusive breast-feeding, and movements in and out of the exclusively breast-fed category, are considered.

The nutritional status of the elderly in Russia, 1992 through 1994.

OBJECTIVESnThe purpose of this study was to ascertain how economic reform has affected nutritional well-being of the elderly in the Russian Federation.nnnMETHODSnA sample of more than 2932 Russians 60 years of age and older was selected from a nationally representative survey of Russian households. A 24-hour dietary recall and data on weight, height, and socioeconomic status were collected during 1992 and 1993 and from a separate nationally representative sample of 1955 persons in the same age group in 1994.nnnRESULTSnRussias elderly did not experience major declines in economic or nutritional well-being during the first 2 years of the reform period. Dietary composition shifted slightly toward reduced fat consumption. A small proportion of individuals showed signs of underweight. Of those who were underweight in 1992, none had lost more than 3 kg of weight by 1993. Among those 70 years of age and older, none who were underweight had lost any appreciable weight, although half lost small amounts.nnnCONCLUSIONSnMany more underweight elderly people increased than reduced their weight. Mean weight increased among all body mass index groups over the year reported here. However, economic conditions in December 1994 raise concerns.

Community-based screening: association between nutritional risk status and severe disability among rural home-delivered nutrition participants.

Abstract In order to examine the association between high nutritional risk status and severe functional disability (any ADL and any IADL) among a racially diverse sample of community-dwelling older adults participating in the home-delivered nutrition program, a cross-sectional analysis was performed on data collected on all participants (n = 245) in two rural North Carolina counties. Using multivariate logistic models, participants with a high nutritional risk status were 2.4 times more likely to report severe functional disability than those with low or moderate nutritional risk status. Age demonstrated an unexpected inverse association with both nutritional risk status and functional disability. This study supports the conclusion that home-delivered nutrition participants at high risk for poor nutrition are also at high risk for severe functional disability. This underscores the importance of nutritional and functional screening as an antecedent for community-based targeted interventions to help older adults remain independent and in their home.

Does endogeneity matter? A comparison of empirical analyses with and without control for endogeneity

PURPOSEnUsing data from the Cebu Longitudinal Health and Nutrition Survey, we perform an empirical investigation of the effects of endogeneity and unobserved heterogeneity in the analysis of health outcomes.nnnMETHODSnFirst, we lay a theoretical background for this analysis and develop a set of expectations regarding the effects of ignoring endogeneity. Then, by modeling the effect of infant-feeding patterns on time to resumption of menses, we perform parallel analyses with and without control for endogeneity.nnnRESULTSnWe show that in this analysis, as far as the effects of endogeneity are concerned, empirical results do accord with theoretical expectations. There are differences in parameter estimates between models, that lead to somewhat different interpretations.nnnCONCLUSIONSnWe discuss the importance and implications of these findings for epidemiological studies of health outcomes. We outline the steps involved in such an analysis and discuss the practical limitations of the methods, as well as the possible gains.

Longitudinal analysis of the effects of infant-feeding practices on postpartum amenorrhea*

The Cebu Longitudinal Health and Nutrition Survey is used to examine the effect of various components of infant-feeding patterns on return of menses postpartum. The results show that factors such as active suckling, the use of two breasts versus one, breast-feeding on demand versus on a fixed schedule. and the feeding of other milks and of nonnutritive or low-caloric other liquids can be important under selected circumstances. Discrete-time logistic hazards modeling is used to estimate the weekly probability of return to menses.

Non-fatal violence-related injuries in Kingston, Jamaica: a preventable drain on resources.

Using data for a one-year period from the Kingston Public Hospital (KPH) in Jamaica, we describe patterns of non-fatal violence-related injuries, and carry out simulation analysis to estimate rates of hospital admission under various injury reduction scenarios, and the potential savings that can be realized by reducing violent crimes. In this period there were 6107 registered violence-related visits to the KPH representing 11.5% of all recorded visits. Of these 16.6% (1001) were admitted. The most common methods of inflicting injury was by stabbing (52.1%), blunt injuries (37.9%) and gunshot wounds (7.3%). Multivariate analyses indicated that gunshot injuries, stab injuries, being male between the ages of 15 and 44 years, receiving the injury in November or December, and being injured by a stranger or unknown assailant, were significant correlates of a higher probability of admission. Simulation analysis with various injury reduction scenarios indicated decreases in the probability of admission ranging from 12% to 44%, with estimated savings of up to 31% of the annual supplies budget of KPH.

The Effects of Calories and Types of Supplements on Postpartum Amenorrhea in the Philippinesa

n Data on 3080 mother-infant pairs from Cebu in the Philippines were used to conduct a logistics hazards analysis to determine the effect of supplemental calories and the types of supplements that the infant ingests on return to menses. Breast feeding had a significant reduced odds of the mother returning to menses (odds ratio [OR] = 0.15; p 0.0001). Supplemental calories (50 calories/kg body weight) had a significant increased odds of return to menses (OR = 1.16; p 0.05). Other milks accounted for most of the effect of supplemental calories since they increased the odds of return to menses significantly (OR = 1.24 for low milks, p 0.05; OR = 1.78 for high milks, p 0.0001). Only high other liquids had a significant effect (OR = 1.22; p 0.05). Semi-solids had no effect at all, while solid foods reduced the odds of returning to menses (OR = 0.83 for low solids, p 0.05; OR = 0.92 for high solids, not significant). These findings suggest that solid foods do not satisfy the need for suckling and/or are not breast milk substitutes and that mothers breast feed at maximal or near-maximal levels.n