ObjectivesTo validate the self-reported diagnoses of gynaecological and breast cancers in a nationwide prospective cohort study of nursing professionals: the Japan Nurses’ Health Study (JNHS).Design and settingRetrospective analysis of the JNHS.Participants and measuresData were reviewed for 15 717 subjects. The mean age at baseline was 41.6±8.3 years (median: 41), and the mean follow-up period was 10.5±3.8 years (median: 12). Participants are regularly mailed a follow-up questionnaire once every 2 years. Respondents who self-reported a positive cancer diagnosis were sent an additional confirmation questionnaire and contacted the diagnosing facility to confirm the diagnosis based on medical records. A review panel of experts verified the disease status. Regular follow-up, confirmation questionnaires and expert review were validated for their positive predictive value (PPV) and negative predictive value (NPV).ResultsNew incidences were verified in 37, 47, 26 and 300 cervical, endometrial, ovarian and breast cancer cases, respectively. The estimated incidence rates were 22.0, 25.4, 13.8 and 160.4 per 100 000 person-years. These were comparable with those of national data from regional cancer registries in Japan. For regular follow-up, the corresponding PPVs for cervical, endometrial, ovarian and breast cancer were 16.9%, 54.2%, 45.1% and 81.4%, and the NPVs were 100%, 99.9%, 99.9% and 99.9%, respectively. Adding the confirmation questionnaire improved the PPVs to 31.5%, 88.9%, 76.7% and 99.9%; the NPVs were uniformly 99.9%. Expert review yielded PPVs and NPVs that were all ~100%.ConclusionsGynaecological cancer cannot be accurately assessed by self-reporting alone. Additionally, the external validity of cancer incidence in this cohort was confirmed.

Purpose: Although the validity of self-reported osteoporosis is often questioned, validation studies are lacking. This study was performed to investigate how well self-reported diagnoses of osteoporosis agreed with validated clinical information in young and middle-aged women in the Japan Nurses' Health Study (JNHS), a nationwide prospective cohort study of nursing professionals. Patients and Methods: Data were reviewed for 15,717 subjects from the combined cohorts of the JNHS and a preceding pilot study (Gunma Nurses' Health Study). The subjects' mean age at the baseline (BL) survey was 41.6 ± 8.3 years, and the mean followup period was 11.5 ± 4.4 years. Participating nurses were mailed a follow-up questionnaire every 2 years. Respondents who self-reported a positive osteoporosis diagnosis during the study period were sent an additional confirmation questionnaire to corroborate the details. Results: The number (proportion) of women with osteoporosis was 884 (5.6%) [primary osteoporosis, 812 (5.2%); secondary osteoporosis, 72 (0.5%)]. The cumulative incidence of osteoporosis at the age of 40, 50, 60, 70, and 80 years was estimated to be 0.1% (95% confidence interval, 0.1-0.2), 1.1% (0.9-1.3), 7.7% (7.0-8.4), 23.6% (21.6-25.7), and 54.2% (40.2-68.1), respectively. For BL and regular follow-up + expert review versus BL and regular follow-up + confirmation questionnaire + expert review, the positive predictive value (PPV) was 61.3% versus 85.6% and the negative predictive value (NPV) was 98.9% versus 98.2%, respectively. Conclusion: Self-reporting was associated with a high NPV for the incidence of osteoporosis. Although the PPV was slightly lower, additional corroborations by confirmation questionnaire might improve the PPV.

Background: The Japan Nurses’ Health Study (JNHS) is a large-scale, nationwide prospective cohort study of female nurses. This study aimed to examine the validity of self-reported diagnosis of cancer among the JNHS cohort members (N=15,019). Methods: For women who reported any diagnosis of five cancers (stomach, colorectal, liver, lung and thyroid) in the biennial follow-up surveys, an additional outcome survey, medical facility survey, and confirmation of death certificate (DC) were conducted. The JNHS Validation Study Committee (referred to as “the committee”) made a final decision on the reported outcomes. To examine the validity of self-reported diagnosis of cancer, the positive predictive value (PPV) was calculated using the committee’s decision as the gold standard. To examine the validity of the committee’s decision based on self-reports and DCs, PPV was calculated using physician-reported information as the gold standard. Results: The PPV of self-reported diagnosis in the biennial follow-up surveys was 77.8% for stomach, 66.2% for colorectal, 41.7% for liver, 60.2% for lung, and 64.6% for thyroid cancer. The corresponding PPVs in the additional outcome survey were 96.2%, 80.7%, 62.5%, 82.5%, and 96.9%, respectively. The PPV of the committee’s decision was 100% for stomach, 87.5% for colorectal, 94.7% for lung, and 100% for thyroid cancer (data not available for liver cancer). The proportion of DC-only cases among committee-defined cases was below 10% for all cancers except liver cancer (28.6%). Conclusions: The validity of identifying cancer diagnosis based on self-reported information in the JNHS was favorable for stomach, colorectal, lung and thyroid cancer.