Validation of Self-Reported Anthropometric Measures and Body Mass Index in a Subcohort of the DianaWeb Population Study.

ABSTRACT

INTRODUCTION: DianaWeb is a community-based participatory project open to Italian breast cancer patients. The aim of the study was to assess the effectiveness of a lifestyle intervention in improving the prognosis after patients received diagnosis and surgery/chemotherapy. The DianaWeb study uses an interactive Web site (www.dianaweb.org) to monitor patients' lifestyles, and to obtain clinical and anthropometric data. Although detailed instructions for measuring height, body weight, waist circumference, and blood pressure (BP) are provided, individuals might tend to overestimate or underestimate those parameters. The aims of the present study were (1) to compare self-recorded data with those from standardized ambulatory measurements; (2) to determine the trueness of a subject classification in the overweight/obesity or hypertensive subgroup on the basis of the patients' own measurements and estimates; and (3) to identify confounding variables. PATIENTS AND METHODS: We compared self-reported with ambulatory measurements in a subgroup of 200 randomly selected women of approximately 1000 enrolled in the DianaWeb study (from September 2016 to March 2018). RESULTS: Bland-Altman analysis showed a close agreement for self-reported and ambulatory-measured height, weight, and body mass index (BMI). On the contrary, women overestimated waist circumference and underestimated BP. Cohen κ statistics showed fair agreement only for hypertension. Binary logistic regression analysis showed that BMI and diastolic BP self-measurements were biased according to age. CONCLUSION: The results suggest that self-reported height, weight, and BMI are satisfactorily accurate for patients in the DianaWeb study, such as accuracies of overweight/obese and central obesity classification, and that these data can be useful for our research.