Validity of Self-Reported Diagnosis of Osteoporosis in Japan Nurses’ Health Study

Takumi Kurabayashi,¹ Yuki Ideno,² Kazue Nagai,³ Naho Maruoka,³ Kiyoshi Takamatsu,⁴ Toshiyuki Yasui,⁵ Kunihiko Hayashi<sup>3

1</sup>Department of Obstetrics and Gynecology, Niigata City General Hospital, Niigata, Japan; ²Gunma University Center for Mathematics and Data Science, Maebashi, Gunma, Japan; ³Department of International/Community Health Laboratory Sciences, Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan; ⁴Department of Obstetrics and Gynecology, Tokyo Dental College Ichikawa General Hospital, Chiba, Japan; ⁵Department of Reproductive and Menopausal Medicine, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan

Correspondence: Takumi Kurabayashi
Department of Obstetrics & Gynecology, Niigata City General Hospital, 463-7, Shumoku, Chuo-ku, Niigata City, Niigata Prefecture, 950-1197, Japan
Tel +81-25-281-5151
Fax +81-25-281-5169
Email [email protected]

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 follow-up 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.

Keywords: validation, self-reported diagnosis, osteoporosis, prospective cohort study, Japan Nurses’ Health Study