In how many ways can one age successfully? Patterns of wellbeing in the Lothian Birth Cohort, 1936

Abstract

This thesis explored cognitive, psychosocial, and physical domains of wellbeing to find out their contribution to successful ageing in 70-year old individuals. Discovering groups with different patterns of wellbeing and their correlates may be informative about what constitutes success in old age. The objectives were to find out whether distinct groups within and across domains of wellbeing existed, and to find out the variables associated with the resulting groups. Using a cross-sectional design on the Lothian Birth Cohort 1936 (LBC1936, maximum n = 1091), which is a group of community-dwelling 70 year-olds, latent class analysis (LCA) was used to explore possible patterns of ageing in domains of cognitive, psychosocial, and physical function. Demographic, personality, and lifestyle variables that were not used in the LCA were used to characterise the resulting groups. The first study investigated cognitive ability. Individuals were grouped according to their scores on general cognitive ability (g), memory, and speed. I accepted a 3-group solution, including High- (n = 749, 69%), Average- (n = 303, 28%), and Low- (n = 39, 4%) cognition groups. Results indicated the presence of a strong dimension: people who did well on one component also did well on others, and failed to show any indication of uneven patterns of scores. In the second study on psychosocial wellbeing individuals were grouped according to their scores on physical function, quality of life, and emotional wellbeing. A 5-group solution was accepted. High (n =515, 42.7%), Average (n = 417, 38.3%), and Poor (n = 37, 3.4%) Wellbeing groups were identified; however, contrasting patterns of wellbeing across components were noticed in the two other groups: one group scored relatively highly on physical function, but low on emotional wellbeing (High Function/ Low Spirits, n = 60, 5.5%), while another group showed low physical function but relatively high emotional wellbeing (Low Function/High Spirits, n = 62, 5.7%). The next study investigated the physical fitness domain: groups were determined on physical fitness, lack of inflammation, and lack of morbidity. Two groups, High Physical Fitness (n = 757, 73.3%) and Low Physical Fitness (n = 291, 26.7%) were identified, which, like the cognitive domain, also indicated a continuous pattern of wellbeing. In the final study individuals were grouped according to their scores on all variables reflecting cognitive, psychosocial, and physical function. I identified 3 groups showing high or uneven patterns of wellbeing. The majority of individuals fell in the High Wellbeing group (n = 712, 65.3%). The two other groups contained either individuals scoring high on cognitive measures but poorly on psychosocial and physical measures (the Low Bio-Psychosocial group, n = 158, 14.5%), or individuals scoring low on cognitive measures but highly on psychosocial and physical measures (the Low Cognition group, n = 221, 20.3%). Intelligence, personality and health behaviours showed salient differences amongst the groups in all studies. Overall, high childhood cognitive ability, low scores on Neuroticism, and avoiding smoking were associated with high wellbeing. Overall, results demonstrated that although wellbeing in old age is primarily dimensional, there is evidence of groups showing uneven patterns of function, indicating that individuals could show relatively successful patterns in some areas of wellbeing despite relatively poor functioning in other areas. Awareness of the importance of lifelong intelligence and personality traits and health practices to later-life wellbeing amongst health-care professionals and policymakers may help address risk-prevention, and improve compliance and patient-practitioner relationships to reduce health inequalities.