Lifecourse correlates of self-rated health and associations with subsequent mortality: findings from the Hertfordshire Cohort Study.

BACKGROUND: Poor self-rated health (SRH) has been shown to predict adverse health outcomes among older people, however these associations have traditionally only been considered at one point in the lifecourse, usually midlife or later. Here we examined lifecourse correlates of SRH in early, mid and later life, relating these to subsequent risk of mortality in a community-dwelling cohort.

METHODS: 2989 men and women from the Hertfordshire Cohort Study (HCS) were included in this study. The HCS was initially retrospective and linked contemporary health outcome data to early life data available from health ledgers but investigations from baseline (1998-2004, aged 59-73) onwards have been prospective. At baseline, participants completed an initial clinic visit, which included questionnaire assessment of SRH, reported as 'excellent', 'very good', 'good', 'fair', or 'poor'. Socioeconomic, lifestyle, mental health and demographic information was also collected. Deaths were recorded from baseline to 31/12/2018. Baseline characteristics in relation to SRH were examined using sex-stratified ordinal logistic regression; these factors were examined in relation to mortality using sex-stratified Cox regression. Statistically significant exposures were then included in sex-stratified mutually-adjusted models.

RESULTS: In mutually-adjusted analysis, numerous contemporaneous correlates of poorer SRH in the seventh decade were identified and included obesity, lower physical activity, greater comorbidity and higher levels of depression among men and women. For example, odds ratios for being in a lower category of SRH were as follows: obese (BMI≥30) vs underweight/healthy (BMI<25) (men 1.60 (1.21, 2.11), women 1.65 (1.25, 2.17)) and per additional system medicated (men 1.62 (1.47, 1.77), women 1.53 (1.41, 1.66)). By contrast, factors earlier in the lifecourse (early growth, age left full-time education) were not associated with SRH in late adulthood. 36% of men and 26% of women died during follow-up. Hazard ratios (95% CI) for mortality per lower category of SRH were 1.22 (1.10,1.36) among men and 1.17 (1.01,1.35) among women after adjustment for age, BMI, smoking, physical activity, diet quality, education, home ownership status, comorbidity level and depression levels, suggesting residual confounding by other unrecorded factors that are related to SRH.

CONCLUSIONS: Poorer SRH in the seventh decade was a risk factor for mortality. Importantly modifiable adverse health behaviours in the seventh decade, such as low physical activity, were associated with poorer SRH and later mortality after adjustment for socioeconomic factors and comorbidity level. By contrast early growth and education were not related to later SRH. These data suggest that attention to lifestyle in late midlife may be associated with better SRH and subsequent health outcomes, highlighting the value of intervention at this stage of the lifecourse.