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Biomedical subjects

I Romieu

Publications and source records attributed to I Romieu.

At least 55 records · Page 3Linked to original sources
PubMed1996

Breast cancer and lactation history in Mexican women.

The authors conducted a case-control study in Mexico City between September 1990 and December 1992 to determine whether a dose-response relation could be observed between duration of lactation and the risk of breast cancer. Cases, women aged 20-75 years, were identified through six hospitals in Mexico City (n = 349) and were interviewed to obtain data on risk factors for breast cancer, including a detailed history of lactation. Controls (n = 1,005) were selected from the general population using the Mexican national sampling frame. Parous women who had ever lactated had a reduction in breast cancer risk (age-adjusted odds ratio (OR) = 0.39, 95% confidence interval (CI) 0.25-0.62). A small decreasing trend of breast cancer risk in relation to duration of lactation (p < 0.001) was observed. Compared with parous women who had never breast-fed, women who had breast-fed for 12-24 months had an age-adjusted odds ratio of 0.47 (95% CI 0.27-0.83). A stronger protective effect was observed with lactation duration for the first live birth among pre- and postmenopausal women (for 4-12 months of lactation, OR = 0.56 (95 percent CI 0.32-0.96) and OR = 0.48 (95 percent CI 0.29-0.81) in pre- and postmenopausal women, respectively). Adjusting for potentially confounding factors modified these results only slightly. The declining trend in fertility and lactation among Mexican women could lead to a major epidemic of breast cancer such as that observed in Western countries.

Adult↗
PubMed1996

Effects of air pollution on the respiratory health of asthmatic children living in Mexico City.

The relation between air pollution and the exacerbation of childhood asthma was studied in a panel of 71 children (aged 5 to 7 yr) with mild asthma who resided in the northern part of mexico City. During the follow-up, ambient measures of particulate matter less than 10 microns (PM10, 24-h average) and ozone (1-h maximum) frequently exceeded the Mexican standards for these contaminants. The peak expiratory flow rate (PEFR) was strongly associated with PM10 levels and marginally with ozone levels. Respiratory symptoms (coughing, phlegm production, wheezing, and difficulty breathing) were associated with both PM10 and ozone levels. An increase of 20 micrograms/m3 of PM10 was related to an 8% increase in lower respiratory illness (LRI) among children on the same day (95% confidence interval [CI] = 1.04-1.15), and an increase of 10 micrograms/m3 in the weekly mean of particulate matter less than 2.5 microns (PM2.5) was related to a 21% increase in LRI (95% CI = 1.08-1.35). A 50 parts per billion (ppb) increase in ozone was associated with a 9% increase in LRI (95% CI = 1.03-1.15) on the same day. We concluded that children with mild asthma are affected by the high ambient levels of particulate matter and ozone observed in the northern part of Mexico City.

Air Pollutants↗
PubMed1996

Dietary and environmental determinants of blood and bone lead levels in lactating postpartum women living in Mexico City.

Despite the recent declines in environmental lead exposure in the United States and Mexico, the potential for delayed toxicity from bone lead stores remains a significant public health concern. Some evidence indicates that mobilization of lead from bone may be markedly enhanced during the increased bone turnover of pregnancy and lactation, resulting in lead exposure to the fetus and the breast-fed infant. We conducted a cross-sectional investigation of the interrelationships between environmental, dietary, and lifestyle histories, blood lead levels, and bone lead levels among 98 recently postpartum women living in Mexico City. Lead levels in the patella (representing trabecular bone) and tibia (representing cortical bone) were measured by K X-ray fluorescence (KXRF). Multivariate linear regression models showed that significant predictors of higher blood lead included a history of preparing or storing food in lead-glazed ceramic ware, lower milk consumption, and higher levels of lead in patella bone. A 34 micrograms/g increase in patella lead (from the medians of the lowest to the highest quartiles) was associated with an increase in blood lead of 2.4 micrograms/dl. Given the measurement error associated with KXRF and the extrapolation of lead burden from a single bone site, this contribution probably represents an underestimate of the influence of trabecular bone on blood lead. Significant predictors of bone lead in multivariate models included years living in Mexico City, lower consumption of high calcium content foods, and nonuse of calcium supplements for the patella and years living in Mexico City, older age, and lower calcium intake for tibia bone. Low consumption of milk and cheese, as compared to the highest consumption category (every day), was associated with an increase in tibia bone lead of 9.7 micrograms Pb/g bone mineral. The findings of this cross-sectional study suggest that patella bone is a significant contributor to blood lead during lactation and that consumption of high calcium content foods may protect against the accumulation of lead in bone.

Adolescent↗
PubMed1995

Effects of urban air pollutants on emergency visits for childhood asthma in Mexico City.

The metropolitan area of Mexico City, Mexico, has serious air pollution problems. Although air contaminants may contribute to clinical asthma, there are at present no data on the relation between air pollution exposure and childhood asthma in Mexico City. The authors reviewed data on emergency visits from January to June 1990 at one major pediatric hospital in Mexico City. They used a Poisson regression model to study the relation between the number of daily emergency visits for asthma and air pollutant levels. The levels of ozone and sulfur dioxide-exposure were significantly associated with the number of emergency visits for asthma. After adjustment for potential confounding factors, the multivariate regression model predicted that an increase of 50 ppb in the 1-hour maximum ozone level would lead to a 43% increase in the number of emergency visits for asthma on the following day. Exposure to high ozone levels (> 110 ppb) for 2 consecutive days increased the number of asthma-related emergency visits by 68 percent. The results of this study suggest that ozone exposure is positively associated with the number of children's emergency visits for asthma in Mexico City.

Adolescent↗
PubMed1995

Environmental urban lead exposure and blood lead levels in children of Mexico City.

Lead contamination is now a leading public health problem in Mexico. However, there are few data on the lead content of various environmental sources, and little is known about the contribution of these sources to the total lead exposure in the population of children residing in Mexico City. We conducted a cross-sectional study in a random sample of 200 children younger than 5 years of age who lived in one of two areas of Mexico City. Environmental samples of floor, window, and street dust, paint, soil, water, and glazed ceramics were obtained from the participants' households, as well as blood samples and dirt from the hands of the children. Blood lead levels ranged from 1 to 31 micrograms/dl with a mean of 9.9 micrograms/dl (SD 5.8 micrograms/dl). Forty-four percent of the children 18 months of age or older had blood lead levels exceeding 10 micrograms/dl. The lead content of environmental samples was low, except in glazed ceramic. The major predictors of blood lead levels were the lead content of the glazed ceramics used to prepare children's food, exposure to airborne lead due to vehicular emission, and the lead content of the dirt from the children's hands. We conclude that the major sources of lead exposure in Mexico City could be controlled by adequate public health programs to reinforce the use of unleaded gasoline and to encourage production and use of unleaded cookware instead of lead-glazed ceramics.

Adult↗
PubMed1994

Use of lead-glazed ceramics is the main factor associated to high lead in blood levels in two Mexican rural communities.

Two isolated rural communities of Mexico were studied to assess the possible relationship between lead-glazed ceramics use and lead exposure. Women from these communities (n = 98) were asked to participate by filling out a general-purpose and exposure questionnaire in order to assess the individual contribution of ceramics to lead exposure. Blood samples were withdrawn to measure lead in blood and erythrocytic zinc protoporphyrin levels. Results were analyzed by multiple regression in order to find predictors of the dependent variables. Significant association between lead in blood and erythrocytic zinc protoporphyrin levels was identified with the following variables: storage in lead-glazed ceramics, cooking in lead-glazed ceramics, and meat and cheese consumption. The adjusted regression models explained 20-23% of the variance of the dependent variables (lead in blood and erythrocytic zinc protoporphyrin). A significant association (r2 = .38) was observed between lead in blood and lead in food prepared in lead-glazed ceramics in a subsample of 28 women. Results indicate that lead-glazed ceramics use may be the main predictor of lead in blood and erythrocytic zinc protoporphyrin levels in the rural communities studied.

Adolescent↗
PubMed1994

Sources of lead exposure in Mexico City.

Many countries, including Mexico, are facing a largely unrecognized epidemic of low-level lead poisoning. Mexico is the sixth largest lead-producing country in the world, and 40% of its production is used locally in different industrial processes that cause lead contamination of the environment. The major sources and pathways of lead exposure among the Mexican population are gasoline emissions, lead-glazed ceramics, leaded paint, and lead in canned foods and beverages. In this paper we present evidence for the presence of lead in different environmental media and its impact on blood lead levels of the Mexican population. Although during the last few years important measures have been implemented to decrease lead exposure, our findings suggest that lead poisoning is still an important problem in Mexico. There is an urgent need for regulatory policies that implement stricter control to protect the Mexican population. There is also a need to develop adequate programs to reduce the lead burden and the associated health effects in the population that has been chronically exposed.

Ceramics↗
PubMed1992

Air pollution and school absenteeism among children in Mexico City.

To determine the acute effects of ozone exposure, the authors conducted a short follow-up study of respiratory illness in a population of 111 preschool children frequently exposed to ozone levels that regularly exceed 0.120 parts per million (ppm). The children attended a private kindergarten in the southwestern part of Mexico City. Parents completed a questionnaire on demographic data, medical history, and potential sources of indoor air pollution. To determine the relation of ozone and respiratory-related school absenteeism, the authors used a logistic regression model for longitudinal data. During the 3-month follow-up, 50% of the children had at least one respiratory-related absenteeism period, and 11.7% had two or more. Children exposed for 2 consecutive days to high ozone levels (> or = 0.13 ppm) had a 20% increment in the risk of respiratory illness. For children exposed for 2 consecutive days to a high ozone level and the previous day to low temperature (< or = 5.1 degrees C), the risk reached 40% (odds ratio = 1.44, 95% confidence interval 1.37-1.52). This study suggests that ozone exposure might be positively associated with the risk of respiratory illness in children and that it may have an interactive effect with low temperature exposure.

Absenteeism↗
PubMed1991

Lead-glazed ceramics as major determinants of blood lead levels in Mexican women.

The aim of this study was to determine the main contributors to blood lead levels in a population of women from middle to low socioeconomic status in the southwestern part of Mexico City. Within this area, the authors selected a random sample of 200 women. Age ranged from 21 to 57 years, with a mean of 36 years. Among 99 women who agreed to participate in this study, blood lead levels ranged from 1 to 52 micrograms/dL, with a mean of 10.6 micrograms/dL. Five percent of the women had a blood lead level over 25 micrograms/dL and 22% over 15 micrograms/dL. There was no significant trend in blood levels according to age. The main determinants of blood lead levels were higher socioeconomic status (presence of telephone in the house, t-test, p = 0.01) and using lead-glazed ceramics (LGC) to prepare food (t-test, p less than 0.005). There was a significant increasing trend in blood lead levels with increasing frequency of consumption of food prepared in LGC (test for trend, p = 0.0008). Among the dishes prepared in LGC, the main determinant was the consumption of stew. Time spent outdoors and consumption of tap water and of canned food were not important determinants of blood lead levels. The population attributable risk of high blood level (less than 15 micrograms/dL) due to the use of LGC was 58%. These findings demonstrate the major role of traditional pottery as a contributor to blood lead levels in this population and emphasize the need for interventions to produce lead-free pottery.

Adult↗
PubMed1991

Modeling the AIDS epidemic in Mexico City.

To study the future course of the AIDS epidemic in Mexico City, we use an open compartmental model to forecast new AIDS cases among homosexual and bisexual males and among heterosexual males and females. For each group three compartments are defined: uninfected persons, infected but asymptomatic persons, and persons diagnosed with AIDS. It is assumed that the AIDS epidemic will follow the propagation of infectious disease model, where spread of infection is proportional to the product of the number of healthy persons and the number of infected ones. The compartmental model is represented by a system of nonlinear differential equations describing the rate of change in the number of persons in each compartment. The impact of preventive measures is explored by decreasing the probability of HIV transmission, which is one of the model parameters representing behavioral patterns. By April 1989, 491 AIDS cases had been reported in Mexico City and classified as sexually related. Our model predicts that the AIDS incidence will continue to rise in Mexico City for the foreseeable future and will spread among the heterosexual population. Decreasing the transmission probability by 10% in all groups (through education programs) will result in a decrease of 18.1% in the number of accumulated cases over a 5-year period. A 20% decrease would prevent more than 31% of the cases. We conclude that mathematical models can be valuable in predicting the spread of the AIDS epidemic and the impact of behavioral change on its spread.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Oral contraceptives and breast cancer. Review and meta-analysis.

To evaluate the relation between use of oral contraceptives and the incidence of breast cancer, the authors reviewed the epidemiologic literature and used quantitative methods to summarize the data. Study results for any use of oral contraceptives were pooled using a model that accounted for both interstudy and intrastudy variability. The authors also explored interstudy variability and modeled a duration-effect relation between oral contraceptive use and breast cancer. Case-control and follow-up studies were considered separately. Overall, the authors observed no increase in the risk of breast cancer for women who had ever used oral contraceptives, even after a long duration of use. These results were consistent across study design. However, data combined from case-control studies revealed a statistically significant positive trend (P = 0.001) in the risk of premenopausal breast cancer for women exposed to oral contraceptives for longer duration. This risk was predominant among women who used oral contraceptives for at least 4 years before their first term pregnancy (relative risk = 1.72; 95% confidence interval = 1.36 to 2.19). Additional study is required to determine whether this finding in a subgroup of exposed women is confirmed and whether the risk remains increased with advancing age.

Adult↗
PubMed1990

Food predictors of plasma beta-carotene and alpha-tocopherol: validation of a food frequency questionnaire.

Nutrient intakes from a food frequency questionnaire are usually calculated as the product of frequency of intake and nutrient composition of the food, summed over the food items. This involves assumptions about the accuracy of recording, food composition data, stability during storage and preparation, and bioavailability. This usual method of calculation was compared with one using empirical weights derived by multivariate linear regression. Food intakes reported on a food frequency questionnaire by Boston, Massachusetts, area subjects in 1982-1985 were used to predict plasma levels of beta-carotene among 370 male and female nonsmokers and plasma levels of alpha-tocopherol among 339 male and female nonusers of vitamin supplements. Nutrient intake computed using empirical weights yielded a significant correlation with plasma beta-carotene (r = 0.43, p = 0.0001), similar to the correlation using nutrient intake calculated from food composition tables (r = 0.38, p = 0.0001). However, the use of empirical weights significantly improved the correlation of vitamin E intake with plasma alpha-tocopherol levels (r = 0.32, p = 0.0001), compared with the weak correlation obtained using the food composition table method to calculate intake (r = 0.16). The results support the validity of published food composition data used to compute carotenoid intake and illustrate the potential utility of empirically derived weights for foods to predict plasma levels of some nutrients.

Adolescent↗
PubMed1990

Urban air pollution in Latin America and the Caribbean: health perspectives.

In the last few years, air pollution has become a major issue in some countries of Latin America and the Caribbean because of urban development and growing industrialization. In addition to industrial processes often concentrated in the cities, vehicle emission and stationary-source fuel combustion are the primary sources of air pollution. Although air-quality standards have been established in some Latin American countries, these are frequently exceeded. Adverse health effects of air pollution have been mainly associated with the following pollutants: sulfur dioxide and particulate matter, photochemical oxidants, nitrogen dioxide and carbon monoxide, and lead. Short-term as well as long-term effects can be expected at levels exceeding WHO guidelines. The Latin American urban areas most affected by anthropogenic pollutant emissions are: the area of São Paulo (Brazil), the city of Santiago (Chile) and the metropolitan area of Mexico City. However, situations similar to those prevailing in these cities could well occur in other cities of Latin America and the Caribbean. The population exposed to air-pollutant levels exceeding WHO guidelines can be estimated to 81 million or 26.5% of the total urban population of Latin America and 19% of its total population. These estimates correspond to 30 million children (0-14), 47 million adults (15-59) and 4 million elderly people (60+). To date a very limited number of epidemiological studies have been carried out to determine the potential health effects of air pollutants in Latin America. To obtain a rough estimate, a scenario was hypothesized in which subjects living in cities would be exposed to a given level of air pollutant, using data from the international literature to extrapolate the expected number of events in different strata of the hypothetical population. The estimated health effects are considerable and warrant priority control intervention. This is true although epidemiological studies are needed to evaluate the health impact of specific pollutant compounds as well as their interactions in Latin American populations exposed to high levels of pollution.

Adolescent↗
PubMed1990

[Hepatitis B at the Dakar Dental School].

Numerous studies have revealed the personal risk of contamination of the virus hepatitis B (HBV). Dental surgeons are chiefly concerned about their almost continual contact, professionally, with blood and saliva. The authors report the results of a study done at the Dental Institute of Dakar. This study revealed the importance of AgHBS and its different functions during the period of observation. A particular point of this study is to emphasis subjects of serology, notably AgHBS+ Anti HBC-, which produce an alternative virus. This study, which is being followed up, has already enabled the commencement of disease prevention programmes of hepatitis through the vaccination of some students: protecting both the dental surgeons and their patients.

Adult↗
PubMed1990

HIV-2 link to AIDS in West Africa.

To date, very little is known concerning the clinical spectrum of human immunodeficiency virus type 2 (HIV-2) infection, and the question as to whether HIV-2 will ultimately prove to be as pathogenic as human immunodeficiency virus type I (HIV-1) remains, as yet, unanswered. We reviewed the currently available reports of HIV-2 infection to assess what is known about the extent of HIV-2 pathogenicity as it compares to HIV-1 pathogenicity. There is evidence that HIV-2 is associated with AIDS. Most of this evidence, however, comes from descriptive case-report type data that do not meet the basic requirements for defining causality. The most significant problems are the lack of control groups and the absence of a documented temporal relationship with HIV-2 infection preceding the development of AIDS. Comparisons of the epidemiology and disease association between HIV-1 and HIV-2 in Africa may suggest relative pathogenic effects. Although certain comparisons between HIV-2 and HIV-1 are difficult to make, we conclude on the basis of existing data that the pathogenic effects and the natural history of HIV-2 are distinct from those of HIV-1.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Prospective study of oral contraceptive use and risk of breast cancer in women.

In 1976, 118,273 female nurses 30-55 years of age with no history of cancer completed a questionnaire regarding possible risk factors. By 1986, after 1,137,415 person-years of follow-up, we had documented 1,799 newly diagnosed cases of breast cancer. Compared with the risk of breast cancer for nonusers of oral contraceptives, the multivariate relative risks were 1.07 (95% confidence interval, 0.97-1.19) for all users, 1.06 (95% confidence interval, 0.96-1.18) for past users, and 1.53 (95% confidence interval, 1.06-2.19) for current users--women who used oral contraceptives up to 2 years before diagnosis of breast cancer. We conclude that overall past use of oral contraceptives is not associated with a substantial increase in the risk of breast cancer. Although we did not find women who used oral contraceptives before the first pregnancy to have an increased risk of breast cancer, the number of women who used oral contraceptives for a long duration in early reproductive life was too small to permit firm conclusions regarding the risk in this subgroup.

Adult↗
PubMed1989

Prevalence of hepatitis B markers among hospital workers in Senegal.

A total of 775 serum samples from men and women working in hospitals in Dakar, Senegal, were tested for serological markers of hepatitis B virus (HBV). HBsAg was detected in 17.8% of the subjects, and 79.2% of the subjects were anti-HBc positive. Among HBsAg carriers 0.04% (5) subjects were HBeAg positive, 0.03% (4) were HBV-DNA positive, and 5.8% (8) were also anti-Delta positive. HBsAg seropositivity was independent of sex and inversely related to age. Duration of service in the hospital was an important predictor of HBsAg seropositivity and the prevalence of seropositive subjects peaked between 2 and 3 years of employment (OR = 1.9; 95% confidence interval [Cl] = 1.1-3.3, when compared to subjects who worked 1 year of less). This peak was critical in the Department of Dentistry, where subjects who worked for 2-3 years experienced a fourfold increase in the risk of HBV infection (OR = 4.0; 95% Cl = 1.8-9.0). Adjusting for age and sex did not modify the results. Within the Department of Dentistry, 15 subjects were HBsAg positive but anti-HBc negative; 12 subjects were retested 1 year later and did not present any markers of past or current HBV infection. These results confirm the increased risk of HBV infection among hospital workers and suggest the presence of HBV variant(s) in Senegal.

Adult↗