Validity of Maternal Report of Birthweight in a Cohort Study and Its Implication on Low Birthweight Rate Using Simulations

Objective:Maternal recall of birthweight is a convenient and cost-effective way to obtainbirthweight measurements when official records are unavailable. It is important to assess thevalidity of maternal recall of birthweight before using these measurements to drawconclusions about a population. Methods:This is secondary analysis of data from a previouscohort study.We analyzed actual and reported birthweights of 200 mother-and-child pairsfrom Southern India. We validated maternal report of birthweight by generating correlationcoefficients, summary statistics, and Bland-Altman plots. We ran simulations to evaluatehow misclassification as low or normal birthweight changed with the mean birthweight of thecohort. Results:Reported birthweight was strongly correlated with actual birthweight(r=0.80, P<0.001); 55%, 78.5%, and 93% of subjects reported values within 50 g, 250 g, and500 g, respectively of actual birthweight. None of sociodemographic covariates wassignificantly associated with the accuracy of maternal recall of birthweight. 7.5% of childrenwere misclassified as either low or normal birthweight by reported birthweight. Simulationsrevealed that increasing the reported and actual birthweights by 500g reduces themisclassification rate from 7.5% to 1.5%. Conclusion:Maternal recall is a sufficientlyaccurate measure of actual birthweight. However, the distribution of actual birthweight in thepopulation must be taken into consideration when classifying babies as low or normalbirthweight, especially in populations where mean birthweight is close to 2500g

Effects of neighborhood socioeconomic status on blood pressure in older adults

ABSTRACT OBJECTIVE To test if the neighborhood socioeconomic status is associated with systolic blood pressure and hypertension in older adults. METHODS A cross-sectional population-based study with a sample of 1,705 older adults from Florianópolis, SC, Southern Brazil. The contextual variable used was the average years of schooling of the head of the household in census tracts. Participants were considered hypertensive when the systolic blood pressure was ≥ 140 mmHg, diastolic ≥ 90 mmHg, or both. Additionally, the use of antihypertensive medication was also considered. Data were analyzed by using multilevel models of logistic and linear regression. RESULTS The average age of the sample was 70.7 years and the average of systolic and diastolic blood pressure was 133.5 mmHg (SD = 20.5 mmHg) and 81.9 mmHg (SD = 12.5 mmHg), respectively. The systolic blood pressure was 4.46 mmHg (95%CI 1.00-7.92) higher and the chance of hypertension was 1.80 (95%CI 1.26-2.57) among those who lived in census tracts with lower level of schooling. When the use of antihypertensive medication was combined with blood pressure levels, none association was found between the outcome and the level of schooling of the census tract. CONCLUSIONS Analytical models more robust (such as multilevel analysis) in Brazil are still little used, with a small number of articles published. Neighborhood socioeconomic status is associated with systolic blood pressure and the chance of hypertension, regardless of individual characteristics.