Validity of self-reported age at menarche in computer-assisted interview among Chinese schoolgirls: a cross-sectional study

OBJECTIVE The attitudes of girls regarding menarche vary according to their cultural backgrounds. Asian girls may hesitate to discuss menarche. Computer-assisted self-administered interviewing (CASI) is considered a valid and effective tool for investigating the timing of menarche; however, the validity of self-reported menarche data from CASI in Chinese culture is currently unknown. We aimed to validate the status and age of menarche attainment by comparing CASI with face-to-face interviewing (FFI). METHODS Based on a cross-sectional study, we collected information regarding the status and age of menarche attainment using CASI and FFI among Chinese schoolgirls. We explored the tools of standard epidemiological indices, including sensitivity, specificity, predictive values and accuracy to examine the capacity of CASI for correctly classifying the status of menarche. Both Pearson and Spearman correlations were calculated for the correlation of age at menarche using CASI with FFI. A Bland-Altman plot was drawn to measure the agreement between the two interview techniques. RESULTS In this study, CASI and FFI were conducted in 3478 schoolgirls with an average age (SD) of 14.3 years (2.46). Menarche attainment was reported in 2496 (71.2%) and 2538 (73.0%) girls using CASI and FFI, respectively. Compared with FFI, the sensitivity, specificity, positive predictive value (PPV), negative predictive value and the accuracy of CASI were 0.97, 0.80, 0.96 and 0.92, respectively. The correlation of age at menarche between CASI and FFI was 0.728. Approximately >95% and 76.3% of the difference in the age at menarche was within 12 months and 3 months, respectively, between the two interview methods. Among primary schoolgirls in grade 5, the sensitivity, specificity, PPV, accuracy and the correlation (0.335) of CASI was lower than those in other subgroups. CONCLUSIONS Overall, the timing of menarche investigated using CASI was valid among all Chinese schoolgirls, except for those in grade 5 or lower.