Role of intergenerational effects on linear growth.
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Current knowledge on the role of intergenerational effects on linear growth is reviewed on the basis of a literature search and recent findings from an ongoing study in Guatemala. Fourteen studies were identified, most of which examined the intergenerational relationships in birth weight. Overall, for every 100 g increase in maternal birth weight, her child's birth weight increased by 10-20 g. The study samples were primarily from developed countries, and birth weight data were extracted from hospital records and/or birth registries. Among the few studies that examined associations between the adult heights of parents and their offspring, correlation coefficients of 0.42-0.5 were reported. None of the studies examined intergenerational relationships in birth length or linear growth patterns during early childhood, preadolescence and/or adolescence. Prospectively collected data from long-term studies being carried out in rural Guatemala provide the first evidence of intergenerational relationships in birth size in a developing country setting. Data were available for 215 mother-child pairs. Maternal birth size was a significant predictor (P < 0.05) of child's birth size after adjusting for gestational age and sex of the child and other potential confounders. Child's birth weight increased by 29 g/100 g increase in maternal birth weight which is nearly twice that reported in developed countries. Similarly, child's birth length increased by 0.2 cm for every 1 cm increase in mother's birth length. The effect of maternal birth weight remained significant even after adjusting for maternal adult size. More evidence from developing countries will help explain the underlying mechanisms and identify appropriate interventions to prevent growth retardation. (+info)
International trends in rates of hypospadias and cryptorchidism.
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Researchers from seven European nations and the United States have published reports of increasing rates of hypospadias during the 1960s, 1970s, and 1980s. Reports of increasing rates of cryptorchidism have come primarily from England. In recent years, these reports have become one focus of the debate over endocrine disruption. This study examines more recent data from a larger number of countries participating in the International Clearinghouse for Birth Defects Monitoring Systems (ICBDMS) to address the questions of whether such increases are worldwide and continuing and whether there are geographic patterns to any observed increases. The ICBDMS headquarters and individual systems provided the data. Systems were categorized into five groups based on gross domestic product in 1984. Hypospadias increases were most marked in two American systems and in Scandinavia and Japan. The increases leveled off in many systems after 1985. Increases were not seen in less affluent nations. Cryptorchidism rates were available for 10 systems. Clear increases in this anomaly were seen in two U.S. systems and in the South American system, but not elsewhere. Since 1985, rates declined in most systems. Numerous artifacts may contribute to or cause upward trends in hypospadias. Possible "real" causes include demographic changes and endocrine disruption, among others. (+info)
Juvenile hypothyroidism among two populations exposed to radioiodine.
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We found an epidemic of juvenile hypothyroidism among a population of self-defined "downwinders" living near the Hanford nuclear facility located in southeast Washington State. The episode followed massive releases of 131I. Self-reported data on 60 cases of juvenile hypothyroidism (<20 years of age) among a group of 801 Hanford downwinders are presented, as well as data concerning the thyroid status of approximately 160,000 children exposed to radioiodine before 10 years of age as a result of the 26 April 1986 Chernobyl explosion in the former Soviet Union. These children were residents of five regions near Chernobyl. They were examined by standardized screening protocols over a period of 5 years from 1991 to 1996. They are a well-defined group of 10 samples. Fifty-six cases of hypothyroidism were found among boys and 92 among girls. Body burdens of 137Cs have been correlated with hypothyroidism prevalence rates. On the other hand, the group of juvenile (<20 years of age) Hanford downwinders is not a representative sample. Most of the 77 cases of juvenile hypothyroidism in the Hanford group were diagnosed from 1945 to 1970. However, the ratio of reported cases to the county population under 20 years of age is roughly correlated with officially estimated mean levels of cumulative thyroid 131I uptake in these counties, providing evidence that juvenile hypothyroidism was associated with radioiodine exposures. Because even subtle hypothyroidism may be of clinical significance in childhood and can be treated, it may be useful to screen for the condition in populations exposed to radioiodine fallout. Although radiation exposure is associated with hypothyroidism, its excess among fallout-exposed children has not been previously quantified. (+info)
Time trends in the mortality rates for tobacco- and alcohol-related cancers within the oral cavity and pharynx in Japan, 1950-94.
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Mortality data of oral cancer over 40 years in Japan were analyzed to investigate time trends of the disease site-specifically and discuss the relation between these trends and the changing patterns of consumption of tobacco and alcohol beverages. Mortality rates were adjusted to the world standard population. In the males, overall oral cancer (ICD-9: 141-149) mortality rates have increased consistently from the lowest value of 1.25 (per 100,000 per year) in 1956 to 2.40 in 1992. The rates for females were constantly lower than those for males, and formed a modest peak of 0.96 in 1979. Regarding site-specific mortality rates, tongue cancer (141) presented a decreasing trend, while oro/hypopharyngeal (146, 148) and mouth (143-145) cancers showed increasing patterns, particularly in males. When the changing patterns of male truncated rates for ages 35-64 were compared with those of the annual consumption of cigarette and alcohol per capita, the time trend of oro/hypopharyngeal cancer mortality was analogous to cigarette consumption rather than to alcohol consumption, mouth cancer vice versa, and tongue cancer was not related to tobacco or alcohol consumption. The present findings suggest that tobacco and alcohol have different site-specific effects on the development of cancers within the oral cavity and pharynx. (+info)
Social environment and year of birth influence type 1 diabetes risk for African-American and Latino children.
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OBJECTIVE: Credible epidemiological data, primarily from European-origin populations, indicate that environmental factors play an important role in the incidence of type 1 diabetes. RESEARCH DESIGN AND METHODS: A population-based registry of incident cases of type 1 diabetes among African-American and Latino children in Chicago was used to explore the influence of individual and neighborhood characteristics on diabetes risk. New cases of insulin-treated diabetes in African-American and Latino Chicagoans aged 0-17 years for 1985-1990 (n = 400) were assigned to one of 77 community areas based on street address. Census tables provided denominators, median household income, percentage of adults > or = 25 years old who had completed high school and college, and a crowding variable for each community area individual-level data were birth cohort, sex, and ethnicity. Outcomes in Poisson regression were sex-, ethnic-, and birth cohort-specific incidence rates. RESULTS: Significant univariate associations between diabetes risk and ethnicity, birth cohort, crowding, and the percentage of adults in each community area who had completed high school and college were observed. African-Americans had a relative risk (RR) of 1.42 (95% CI, 1.14-1.76) compared with Latinos. Risk varied significantly by birth cohort in both ethnic groups. For every 10% increase in the proportion of adults who completed college, the RR for diabetes increased by 25% (RR, 1.25 [95% CI, 1.09-1.44]). Social class variables were significant determinants of risk for African Americans, but not for Latinos. CONCLUSIONS: The strong birth cohort and social class associations observed in this study implicate an infectious exposure linked with age. (+info)
Food safety knowledge and practice among elderly people living at home.
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OBJECTIVE: To assess the food storage knowledge and practice of elderly people living at home. METHODS: Three phase survey data collection: face to face interviews; dietary diaries with a food frequency questionnaire; and follow up interviews. SETTING: Urban Nottingham. PARTICIPANTS: 809 elderly people (aged 65+) randomly selected from general practitioner lists. MAIN OUTCOME MEASURES: Respondent's refrigerator temperature; knowledge of freezer star rating; understanding of "use by" and "sell by" dates; reported ability to read food product safety labels. RESULTS: From a weighted total of 645 refrigerators measured, 451 (70%) were too warm for the safe storage of food (> or = 6 degrees Celsius). Only 41% of respondents (n = 279) knew the star rating of their freezer. Within a smaller sub-sample knowledge of the "use by" and "sell by" dates was good, but 45% of these respondents reported difficulty reading food labels. The storage of foods at inappropriate temperatures was not independent of socioeconomic or demographic status, and tended to be more likely among the poorer and those not living alone. CONCLUSIONS: Food storage practices among the majority of elderly people interviewed in this study do not meet recommended safety standards to minimise the risk of food poisoning. (+info)
A review of the healthy worker effect in occupational epidemiology.
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This review article aims to anatomize sources of the healthy worker effect (HWE) and to summarize advantages and limitations of several approaches frequently proposed to eliminate the HWE. Although the HWE is frequently addressed in the context of selection bias, our review suggests that the selection of occupational cohorts with advantageous health status would preferably be addressed as a source of confounding biases. The authors also conclude that the exclusion of unhealthy workers at employment and the study of active workers are the two main sources of HWE, and that the use of the general population as a comparison group in occupational epidemiology should be avoided if possible. The authors encourage investigators to make distinctions between the underlying factors related to the use of the general population as the comparison group in occupational epidemiology. (+info)
Increase in cervical cancer mortality in Spain, 1951-1991.
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BACKGROUND: The trend in cervical cancer mortality in Spain from 1951 to 1991 is examined. METHODS: Analysis of national mortality statistics calculating age standardised mortality rates and an age-period cohort analysis. A fit to the Gompertz function was made to estimate the influence of the environmental factors on the mortality rates evolution. MAIN RESULTS: The age standardised mortality rate in Spain is lower than in other developed countries (USA or Estonia) and equal to Norwegian and Finland rates; but whereas in these countries the trend is to decrease, the Spanish rate has increased during this period, because of a cohort effect. A misclassification bias could be responsible for the trend in women aged 40 and older but the increasing trend in younger women could not be interpreted as espurious. The Gompertzian analysis suggests an increase in environmental factors causing cervical cancer. CONCLUSIONS: Cervical cancer mortality rates are increasing in Spain because of environmental factors. (+info)