Biomedical subjects

L H Sanin

Publications and source records attributed to L H Sanin.

7 recordsLinked to original sources

PubMed2001

Relation between birth weight and placenta weight.

With the goal to establish a model that relates birth weight to placenta weight, adjusted for the most documented predictors of birth weight, 300 live newborns were studied, all were products of single gestation. Inclusion criteria were newborns with gestational age of 37 weeks or older according to the date of last menstruation, whose mothers did not have diabetes mellitus, high blood pressure, pre-eclampsia, or eclampsia. The weight of the newborn was identified from the anthropometry data collected by previously trained nursing personnel in each of the participating hospitals. Immediately after delivery, the placenta was weighed. Multiple linear regression was used to see the effect of placenta weight and each variable on birth weight. The mean of birth weight was 3,369 g with a standard deviation (SD) of 445 g. Placenta weight had a mean of 537 g (SD: 96 g). The relation between the weight of the placenta and the birth weight was significant, and we found that for each gram increase in placenta weight, birth weight is increased by 1.98 g (SE = 0.25, p < 0.01) and this relation is not linear, since the quadratic term is significant. Placenta weight has a nonlinear relation to the birth weight and is an important predictor of birth weight. Together with the gestational age and the maternal age and size, it explains 32% of the variability of birth weight. Placenta weight can be a 'sentinel' indicator of nutritional and/or environmental problems.

Adult↗

PubMed2000

Blood lead levels and calcium intake in Mexico City children under five years of age.

OBJECTIVE: The relationship between daily calcium intake and blood lead levels was evaluated among children under five years of age living in Mexico City. METHODS: A random sample of 200 children under five years of age, resident in two neighborhoods of Mexico City was selected: Xalostoc, an industrial neighborhood, and Tlalpan, a residential neighborhood (100 from each area). The mothers of these children filled out a questionnaire on predictors of blood lead levels including daily calcium intake. Lead levels were determined from the venous blood samples. Calcium intake was assessed using a short Food Frequency Questionnaire including 11 food items that accounted for 95% of calcium intake in Mexico. RESULTS: The average blood lead level was 9.93 microg dl(-1) (range 1-31 microg dl(-1)). An inverse relationship was observed between blood lead levels and daily calcium intake. This relationship was statistically significant among children aged 13 months-5 years. CONCLUSION: The results suggest that calcium provided a protective effect against lead accumulation in the body among children. Further studies should be undertaken to evaluate this hypothesis through experimental design.

Calcium, Dietary↗

PubMed2000

Determinants of bone and blood lead concentrations in the early postpartum period.

OBJECTIVE: This study investigated determinants of bone and blood lead concentrations in 430 lactating Mexican women during the early postpartum period and the contribution of bone lead to blood lead. METHODS: Maternal venous lead was measured at delivery and postpartum, and bone lead concentrations, measured with in vivo K-x ray fluorescence, were measured post partum. Data on environmental exposure, demographic characteristics, and maternal factors related to exposure to lead were collected by questionnaire. Linear regression was used to examine the relations between bone and blood lead, demographics, and environmental exposure variables. RESULTS: Mean (SD) blood, tibial, and patellar lead concentrations were 9.5 (4.5) microg/dl, 10.2 (10.1) microg Pb/g bone mineral, and 15.2 (15.1) microg Pb/g bone mineral respectively. These values are considerably higher than values for women in the United States. Older age, the cumulative use of lead glazed pottery, and higher proportion of life spent in Mexico City were powerful predictors of higher bone lead concentrations. Use of lead glazed ceramics to cook food in the past week and increased patellar lead concentrations were significant predictors of increased blood lead. Patellar lead concentrations explained one third of the variance accounted for by the final blood lead model. Women in the 90th percentile for patella lead had an untransformed predicted mean blood lead concentration 3.6 microg/dl higher than those in the 10th percentile. CONCLUSIONS: This study identified the use of lead glazed ceramics as a major source of cumulative exposure to lead, as reflected by bone lead concentrations, as well as current exposure, reflected by blood lead, in Mexico. A higher proportion of life spent in Mexico City, a proxy for exposure to leaded gasoline emissions, was identified as the other major source of cumulative lead exposure. The influence of bone lead on blood lead coupled with the long half life of lead in bone has implications for other populations and suggests that bone stores may pose a threat to women of reproductive age long after exposure has declined.

Adult↗

PubMed2000

[Relationship between pregestational body mass index and body composition in the immediate puerperium].

To determine the correlation between pregestational body mass index and certain body composition parameters measured by bioelectric impedance (percentage of fat weight, fat mass, and lean weight) and to compare the body composition of women in immediate puerperal period with non-pregnant women, a cross sectional study was done including 86 women in physiologic puerperal period and 90 healthy non-pregnant women, from the Instituto Mexicano del Seguro Social, in Chihuahua, Mexico, aged 16 to 40 years old. The variables considered were the body mass index (BMI) before pregnancy, percentage of fat, fat mass, lean weight, total water and bio-resistance. Body composition was measured by bioelectric impedance (BIO) from 4 to 12 hours after delivery. Correlation coefFicient for BMI and percentage of fat was r = 0.66 (p < 0.01), and for BMI and fat mass, it was r = 0.74 (p < 0.01). In non-pregnant women the total water was 35.5 +/- 5 L and in women in the immediate puerperal period 38.5 +/- 5 L (p < 0.01). In conclusion, BMI before pregnancy is a suitable predictor for body composition in the puerperal period. However, it does not discriminate important variables such as total body water, so it may be convenient to use BIA for surveillance of body composition during pregnancy.

Adolescent↗

PubMed1998

The influence of bone and blood lead on plasma lead levels in environmentally exposed adults.

There is concern that previously accumulated bone lead stores may constitute an internal source of exposure, particularly during periods of increased bone mineral loss (e.g., pregnancy, lactation, and menopause). Furthermore, the contribution of lead mobilized from bone to plasma may not be adequately reflected by whole-blood lead levels. This possibility is especially alarming because plasma is the main circulatory compartment of lead that is available to cross cell membranes and deposit in soft tissues. We studied 26 residents of Mexico City who had no history of occupational lead exposure. Two samples of venous blood were collected from each individual. One sample was analyzed by inductively coupled plasma-magnetic sector mass spectrometry for whole-blood lead levels. The other sample was centrifuged to separate plasma, which was then isolated and analyzed for lead content by the same analytical technique. Bone lead levels in the tibia and patella were determined with a spot-source 109Cd K-X-ray fluorescence instrument. Mean lead concentrations were 0.54 microg/l in plasma, 119 microg/l in whole blood, and 23.27 and 11.71 microg/g bone mineral in the patella and tibia, respectively. The plasma-to-whole-blood lead concentration ratios ranged from 0.27% to 0.70%. Whole-blood lead level was highly correlated with plasma lead level and accounted for 95% of the variability of plasma lead concentrations. Patella and tibia lead levels were also highly correlated with plasma lead levels. The bivariate regression coefficients of patella and tibia on plasma lead were 0.034 (p<0. 001) and 0.053 (p<0.001), respectively. In a multivariate regression model of plasma lead levels that included whole-blood lead, patella lead level remained an independent predictor of plasma lead level (ss = 0.007, p<0.001). Our data suggest that although whole-blood lead levels are highly correlated with plasma lead levels, lead levels in bone (particularly trabecular bone) exert an additional independent influence on plasma lead levels. It will be important to determine whether the degree of this influence increases during times of heightened bone turnover (e.g., pregnancy and lactation).

Adult↗

PubMed1997

Higher milk intake during pregnancy is associated with lower maternal and umbilical cord lead levels in postpartum women.

Lead exposure and its deleterious effects continue to be a problem in many countries. The lack of effective and safe treatments for low-level intoxication has promoted environmental interventions to control different sources of lead. In this study we evaluated the effect of milk consumption in 1849 mother-and-child pairs participating in the lead surveillance program in Mexico City. The mean lead levels were 11.2 micrograms/dL for maternal blood lead (MBL) and 10.8 micrograms/dL in umbilical cord. The correlation between blood lead and umbilical cord lead was r = 0.74. Forty-eight percent of the MBL exceeded 10 micrograms/dL and 9.5% exceeded 20 micrograms/dL. Maternal blood lead was positively related to the use of lead-glazed ceramic were and to traffic exposure and was inversely related to the consumption of milk and orange juice. Women who reported the consumption of more than 7 glasses of milk per week had a blood lead level of 8.7 micrograms/dL; in comparison, those women who reported a consumption of less than 7 glasses per week had a blood lead level of 11.1 micrograms/dL. Similar findings were observed for lead measured in umbilical cord. The association between lead levels and milk intake remained unchanged after taking in consideration other predictors of blood lead. This study suggests that a simple intervention could reduce lead burden among women and their newborns.

Animals↗

PubMedDate not supplied

Predictors of blood lead levels in agricultural villages practicing wastewater irrigation in Central Mexico.

To investigate whether the agricultural use of untreated wastewater (i.e. crop irrigation) was associated with elevated blood lead levels in a farming population in the Mezquital Valley and which risk factors, other than exposure to untreated wastewater, were associated with elevated blood lead levels, lead levels were measured in venous blood obtained from 735 individuals. Blood samples were analyzed by atomic absorption spectrophotometry. Food habits and dietary intake were gathered by interview, using a semi-quantitative food-frequency questionnaire. The average blood lead level was 7.8 microg/dL (SD 4.66 microg/dL; range 1.2-36.7 microg/dL). 23% of the study population had blood lead levels exceeding 10 microg/dL. The use of lead-glazed ceramics (LGC) was significantly associated with elevated lead levels (p = < 0.001). Other significant variables included age, gender (males), and non-farming-related occupations (e.g., technicians, factory workers). p = 0.005, 0.08, and 0.001, respectively. When the analysis was stratified by the use of LGC for food preparation, an inverse relationship between higher daily calcium intake and blood lead level was detected (beta = - 0.040, p = < 0.05). Thus, blood lead levels were positively associated with the use of LGC. Calcium intake showed a protective effect, maybe by decreasing absorption of lead in the gastrointestinal tract. No association between occupational exposure to untreated wastewater or crop consumption and blood lead levels was detected. Further environmental and health surveillance is recommended.

Adolescent↗