Characteristics of female nonagenarian participants in an observational health study

Background: Inclusion of very elderly participants in health studies is limited, despite the increasing longevity in the population. We aimed to describe characteristics of female nonagenarians who had been retained for a decade in an ongoing, population-based cohort study.
Methods: This study describes 14 female nonagenarians who participated in the 10-year follow-up phase of the Geelong Osteoporosis Study. Their baseline characteristics, from a decade earlier, were compared with 109 fellow participants lost to follow-up.
Results: For nonagenarians at follow-up, mean BMI, relative appendicular mass and blood pressure were in the ideal ranges recommended for all adult ages, whereas mean BMD was in the osteopenic range for the hip and spine. Three (21.4%) of the nonagenarian women were underweight, four (28.6%) were overweight and one was obese; five (38.5%) had hypertension, two (14.3%) required assistance walking, nine (69.2%) had osteoporosis and
two (15.4%) had low lean mass in the sarcopenic range. None of the women smoked or had fallen in the previous year, nine (64.3%) used three or more prescription medications and five (35.7%) used five or more. Comparisons of baseline data collected a decade earlier for the nonagenarians and their peers who were subsequently lost to followup, showed similarities in body habitus, falls, polypharmacy, education, marriage status, socioeconomic status and morbidity. However, the group lost to follow-up were more likely to have had osteoporosis and/or be hypertensive.
Conclusion: We present health-related data for nonagenarian participants of a prospective cohort study. While few differences were found between these participants and age-matched peers for baseline data collected a decade earlier, the nonagenarians who participated in the 10-year follow-up were less likely to have had osteoporosis or hypertension than their peers at recruitment. Further involvement of the very elderly in health research is warranted, since data for this age group are rare.