1Hamad Medical Corporation, CCS Department, Medical Research Centre- Cardiology, Doha, Qatar. Senior consultant. Email: rajvir.aiims@gmail.com
2The University of the West Indies, Faculty of Science and Agriculture, Department of Mathematics & Statistics, Trinidad & Tobago, West Indies. Lecturer. Email: Vrijesh.Tripathi@sta.uwi.edu
3All India Institute of Medical Sciences, Department of Biostatistics, New Delhi, India. Scientist. Email: manikalaivani@gmail.com ]]>
The present study uses data from National Family Health Survey (NFHS-1) 1992-93 (International Institute for Population Sciences 1995) conducted in the state of Tamil Nadu, India. Cox models were developed to analyze the effect of breastfeeding as time varying and time dependent factor on birth intervals. Breastfeeding alone improved the log likelihood up to a higher level in each birth interval. Other factors that entered into the models were: at first birth interval, womens education (high school & above) and working status of women; at second birth interval, survival status of index child alive and husbands education (high school & above), and at third birth interval, breastfeeding more than 22 month were found to be protective factors for next births. Validation of the developed models was done through bootstrapping to predict birth intervals.
Key words: Cox model, Multivariate analysis, Validation, Predictions.
Este estudio utiliza datos de la Encuesta Nacional de Salud Familiar (International Institute for Population Sciences 1995) realizada en el estado de Tamil Nadu, India. Se desarrollaron modelos de Cox para analizar el efecto de la lactancia materna cuando varía en el tiempo y el factor tiempo depende de los intervalos genésicos. La lactancia materna sólo mejora la probabilidad de acceder a un nivel más alto en cada intervalo de nacimiento. Otros factores que entraron en los modelos fueron en el intervalo del primer parto: nivel educativo de la madre (secundaria y superior) y trabajo de la madre; en el intervalo del segundo parto: nivel de supervivencia en el índice de vida infantil y nivel educativo del padre (secundaria y superior), y en el intervalo del tercer parto: lactancia materna más 22 meses. Cada uno de los anteriores es un factor protector para ampliar el intervalo entre nacimientos en el estudio. Además, este estudio confirma los modelos desarrollados en los servicios públicos de predicción para los intervalos genésicos.
]]> Palabras clave: análisis multivariado, modelo de Cox, predicciones, validación.Texto completo disponible en PDF
References
1. Anderson, D. L. & Bean, L. L. (1985), 'Birth spacing and fertility limitation: A behavioral analysis of nineteenth century populationl', Demography 22, 169-183. [ Links ]
2. Blanchard, R. & Bogaert, A. F. (1997), 'Additive effects of older brothers and homosexual brothers in the prediction of marriage and cohabitation', Behavior Genetics 27, 45-54. [ Links ]
3. Cox, D. R. (1972), 'Regression models and life tables (with Discussion)', Journal of the Royal Statistical Society, Series B 34, 187-220. [ Links ]
4. DaVanzo, J. & Starbird, E. (1991), 'Correlates of short interbirth intervals in peninsular Malaysia: Their pathways of influence through breastfeeding and contraceptive use', Studies in Family Planning 22(4 pages 241-254). [ Links ]
5. Dickson, E., Grambsch, P., Fleming, T., Fisher, L. & Langworthy, A. (1989), 'Prognosis in primary biliary cirrohsis: Model for decision making', Hepatology 10(1), 1-7. [ Links ]
6. Dwivedi, S. & Rajvir, S. (2003), 'On assessing the child spacing effect of breastfeeding using cox proportional hazards model with nfhs data', Demography India 32(2), 215-224. [ Links ]
7. Efron, B. & Tibshirani, R. (1993), An Introduction to the Bootstrap, Chapman and Hall, New York. [ Links ]
8. Fox, J. (2008), Applied Regression Analysis, Linear Models, and Related Methods, Sage Publications, Inc., London. [ Links ]
9. Gandotra, M., Retherford, R., Pandey, A., Luther, N. & Mishra, V. (1998), Fertility in India, National Family Health Survey Subject Reports 9, Mumbai: International Institute for Population Sciences; and Honolulu. [ Links ]
10. Harrell, F. E. (2001), Regression Modeling Strategies with Application to Linear Models, Logistic Regression, and Survival Analysis, Springer-Verlag, Berlin. [ Links ]
11. Harrell, F. E., Lee, K. L. & Mark, D. B. (1996), 'Tutorial in Biostatistics Multivariable prognostic models: Issues in developing models, evaluating assumptions and adequacy, and meassuring and reducing errors', Statistics in Medicine 15, 361-387. [ Links ]
12. International Institute for Population Sciences, (1994), National Family Health Survey (MCH and Family Planning), Tamil Nadu 1992, Summary Report , Population Research Centre, The Gandhigram Institute of Rural Health and Family Welfare Trust, Ambathurai R.S. (PRC, Gandhigram), and International Institute for Population Sciences (IIPS), Bombay, India. [ Links ]
13. International Institute for Population Sciences, (1995), National Family Health Survey (MCH and Family Planning): India 1992-93, Summary Report , International Institute for Population Sciences (IIPS), Bombay, India. [ Links ]
14. Kaplan, E. & Meier, P. (1958), 'Nonparametric estimation from incomplete observations', Journal of the American Statistical Association 53, 457-481. [ Links ]
15. Kleinbaum, D. G. (1996), Survival Analysis, A Self Learning Text, 1 edn, Springer-Verlag, New York. [ Links ]
16. Mahmud, M. & Islam, M. (1995), 'Adolescent contraceptive use and its determinants in Bangladesh: Evidence from Bangladesh Fertility Survey 1989.', Contraception 52(3), 181-186. [ Links ]
17. Miller, J. E., Trussell, J., Pabley, A. R. & Vaughan, B. (1992), 'Birth spacing and child mortality in Bangladesh and the Philippines', Demography 29(2), 305-316. [ Links ]
18. Namboodiri, K. & Suchindran, C. M. (1987), Life Table Techniques and Their Applications Studies in Population, Academic Press, Orlando, Florida. [ Links ]
19. Oheneba-Sakyi, Y. & Heaton, T. B. (1993), 'Effects of socio-demographic variables on birth intervals in Ghana', Journal of Comparative Family Studies 24(1), 113-135. [ Links ]
20. Ojha, A. (1998), 'The effect of sex preference on fertility in selected states of India', The Journal of Family Welfare 44(1), 42-48. [ Links ]
21. Palloni, A. & Hantamala, R. (1999), 'The effects of infant mortality on fertility revisited: New evidence from Latin America', Demography 36(1), 41-75. [ Links ]
22. Rajaram, S., Rao, S. & Pandey, A. (1994), 'Birth interval dynamics in Goa: A parity specific analysis', Demography India 23(1), 67-81. [ Links ]
23. Rehman, M. & DaVanzo, J. (1993), 'Gender preference and birth spacing in Matlab, Bangladesh', Demography 30(3), 315-332. [ Links ]
24. Richter, K., Podhisita, C., Chamratrithirong, A. & Soonthorndhada, K. (1994), 'The impact of child care on fertility in urban Thailand', Demography 31(4), 651-662. [ Links ]
25. Rodriguez, G., Hobcraft, J., McDonald, J., Menken, J. & Trussell, J. A. (1984), 'Comparative analysis of the determinants of birth intervals', WFS Comparative Studies(30). [ Links ]
26. Singh, R., Begum, S., Ahuja, R. K., Chandra, P. & Dwivedi, S. N. (2007), 'Prediction of child survival in India using developed Cox PH model: a utility for health policy programmers', Statistics in Transition 8(1), 97-110. [ Links ]
27. Srinivasan, K. (1980), Birth Interval Analysis in Fertility Surveys, {Scientific reports (World Fertility Survey)}, Voorburg and International Statistical Institute, Voorburg and London. [ Links ]
28. Swenson, I. & Thang, N. M. (1993), 'Determinants of birth intervals in Vietnam: A hazard model analysis', Journal of Tropical pediatrics 39, 163-167. [ Links ]
29. Trussell, J. & Charles, H. (1983), 'A hazards model analysis of the covariates of infant and child mortality in Sri Lanka', Demography 20(1), 1-24. [ Links ]
30. Trussell, J., Martin, L., Fledman, R., Palmore, J., Concepcion, M. & Abu Bakar, D. (1985), 'Determinants of birth interval length in the Phillipines, Malaysia and Indonesia: A hazard model analysis', Demography 22(2 pages 145-168). [ Links ]
31. UNFPA, (1997), Reproductive Rights, Reproductive Health and Family Planning, Population Issues , United Nations Fund for Population Activities (UNFPA). [ Links ]
32. Van Houwelingen, J. C. & Cessie, S. (1990), 'Predictive value of statistical models', Statistics in Medicine 8, 1303-1325. [ Links ]
Este artículo se puede citar en LaTeX utilizando la siguiente referencia bibliográfica de BibTeX:
@ARTICLE{RCEv35n2a07,
AUTHOR = {Singh, Rajvir and Tripathi, Vrijesh and Kalaivani, Mani and Singh, Kalpana and Dwivedi, S.N.},
TITLE = {{Determinants of Birth Intervals in Tamil Nadu in India: Developing Cox Hazard Models with Validations and Predictions}},
JOURNAL = {Revista Colombiana de Estadística}, ]]>
YEAR = {2012},
volume = {35},
number = {2},
pages = {289-307}
}