tandmob2: Signal Tandmobiel data, version 2

Description

This is the dataset resulting from a longitudinal prospective dental study performed in Flanders (North of Belgium) in 1996 -- 2001. The cohort of 4\,468 randomly sampled children who attended the first year of the basic school at the beginning of the study was annualy dental examined by one of 16 trained dentists. The original dataset consists thus of at most 6 dental observations for each child.

The dataset presented here contains mainly the information on the emergence and caries times summarized in the interval-censored observations. Some baseline covariates are also included here.

For more detail on the design of the study see Vanobbergen et al. (2000).

This data set was used in the analyses presented in Komárek et al. (2005), in Lesaffre, Komárek, and Declerck (2005) and in Komárek and Lesaffre (2007).

IMPORTANT NOTICE: It is possible to use these data for your research work under the condition that each manuscript is first approved by Prof. Emmanuel Lesaffre Biostatistical Centre Katholieke Universiteit Leuven Kapucijnenvoer 35 B-3000 Leuven Belgium <emmanuel.lesaffre@med.kuleuven.be>

Usage

data(tandmob2)

Arguments

Format

a~data frame with 4\,430 rows (38 sampled children did not come to any of the designed dental examinations) and the following variables

IDNR

identification number of a child

GENDER

character boy or girl

GENDERNum

numeric, 0 = boy, 1 = girl

DOB

character, date of birth in the format DDmmmYY

PROVINCE

factor, code of the province with

0 =: Antwerpen
1 =: Vlaams Brabant
2 =: Limburg
3 =: Oost Vlaanderen
4 =: West Vlaanderen

EDUC

factor, code of the educational system with

0 =: Free
1 =: Community school
2 =: Province/council school

STARTBR

factor, code indicating the starting age of brushing the teeth (as reported by parents) with

1 =: [0, 1] years
2 =: (1, 2] years
3 =: (2, 3] years
4 =: (3, 4] years
5 =: (4, 5] years
6 =: later than at the age of 5

FLUOR

binary covariate, 0 = no, 1 = yes. This is the covariate fluorosis used in the paper Komárek et al. (2005).

BAD.xx

binary, indicator whether a deciduous tooth xx was removed becaues of orthodontical reasons or not. xx takes values 53, 63, 73, 83 (deciduous lateral canines), 54, 64, 74, 84 (deciduous first molars), 55, 65, 75, 85 (deciduous second molars).

EBEG.xx

lower limit of the emergence (in years of age) of the permanent tooth xx. NA if the emergence was left-censored. xx takes values 11, 21, 31, 41 (permanent incisors), 12, 22, 32, 42 (permanent central canines), 13, 23, 33, 43 (permanent lateral canines), 14, 24, 34, 44 (permanent first premolars), 15, 25, 35, 45 (permanent second premolars), 16, 26, 36, 46 (permanent first molars), 17, 27, 37, 47 (permanent second molars).

EEND.xx

upper limit of the emergence (in years of age) of the permanent tooth xx. NA if the emergence was right-censored. xx takes values as for the variable EBEG.xx.

FBEG.xx

lower limit for the caries time (in years of age, `F' stands for `failure') of the permanent tooth xx. NA if the caries time was left-censored. xx takes values as for the variable EBEG.xx.

FEND.xx

upper limit for the caries time (in years of age, `F' stands for `failure') of the permanent tooth xx. NA if the caries time was right-censored. xx takes values as for the variable EBEG.xx. Unfortunately, for all teeth except 16, 26, 36 and 46 almost all the caries times are right-censored. For teeth 16, 26, 36, 46, the amount of right-censoring is only about 25%.

Txx.DMF

indicator whether a deciduous tooth xx was decayed or missing due to caries or filled on at most the last examination before the first examination when the emergence of the permanent successor was recorded. xx takes values 53, 63, 73, 83 (deciduous lateral incisors), 54, 64, 74, 84 (deciduous first molars), 55, 65, 75, 85 (deciduous second molars).

Txx.CAR

indicator whether a~deciduous tooth xx was removed due to the orthodontical reasons or decayed on at most the last examination before the first examination when the emergence of the permanent successor was recorded.

Source

Biostatistical Centre, Katholieke Universiteit Leuven, Kapucijnenvoer 35, 3000 Leuven, Belgium URL: http://med.kuleuven.be/biostat/ Data collection was supported by Unilever, Belgium. The Signal Tandmobiel project comprises the following partners: D. Declerck (Dental School, Catholic University Leuven), L. Martens (Dental School, University Ghent), J. Vanobbergen (Oral Health Promotion and Prevention, Flemish Dental Association), P. Bottenberg (Dental School, University Brussels), E. Lesaffre (Biostatistical Centre, Catholic University Leuven), K. Hoppenbrouwers (Youth Health Department, Catholic University Leuven; Flemish Association for Youth Health Care).

References

Komárek, A., Lesaffre, E., $Harkanen,$ T., Declerck, D., and Virtanen, J. I. (2005). A Bayesian analysis of multivariate doubly-interval-censored dental data. Biostatistics, 6, 145--155.

Komárek, A. and Lesaffre, E. (2007). Bayesian accelerated failure time model for correlated interval-censored data with a normal mixture as an error distribution. Statistica Sinica, 17, 549--569.

Lesaffre, E., Komárek, A., and Declerck, D. (2005). An overview of methods for interval-censored data with an emphasis on applications in dentistry. Statistical Methods in Medical Research, 14, 539--552.

Vanobbergen, J., Martens, L., Lesaffre, E., and Declerck, D. (2000). The Signal-Tandmobiel project -- a longitudinal intervention health promotion study in Flanders (Belgium): baseline and first year results. European Journal of Paediatric Dentistry, 2, 87--96.