Apolipoprotein E ε4 and cognitive function after surgery in middle-aged and elderly Danish twins.

BACKGROUND: Transient cognitive impairment is common in adult patients of all ages following anaesthesia and surgery. Apolipoprotein E (APOE) ε4 carriers may have a larger deterioration in short-term cognitive function after major surgery compared with APOE ε4 noncarriers. OBJECTIVES: The aim was to examine the effect of APOE ε4 on the association between exposure to surgery and anaesthesia, and subsequent cognitive functioning. A more pronounced deterioration in cognitive function in APOE ε4 carriers was hypothesised. DESIGN: An observational cross-sectional and a 6 to 10 years longitudinal twin cohort design. SETTING: Survey and register study of 2936 Danish twins aged 45 to 92 years. MAIN OUTCOME MEASURES: Cognitive function was assessed using five age-sensitive cognitive tests. In the cross-sectional study, we compared twins exposed to surgery with a reference group (unexposed). Linear regression models were used adjusting for sex and age and stratified by APOE ε4 carrier status. In the longitudinal cognitive follow-up study 1671 twins participated. Intrapair analyses were also performed using 70 same-sexed twin pairs concordant for APOE ε4 carrier status, but discordant for major surgery. RESULTS: APOE ε4 carriers had lower cognitive scores compared with noncarriers, and this was statistically significant in elderly twins 70+ years of age (mean difference, -0.67; 95% CI, -1.14 to -0.17). There was no significant impact on cognitive function after surgery according to APOE ε4 carrier status in the cross-sectional study. Similarly, there was no APOE ε4 modification in the longitudinal study. Also, in the intrapair analyses no evidence was found of lower cognitive score after major surgery compared with the nonexposed cotwins among APOE ε4 carriers. CONCLUSION: No evidence was found of more pronounced long-term deterioration in cognitive function after surgery among APOE ε4 carriers, but elderly APOE ε4 carriers in general performed worse on the cognitive tests than noncarriers.

No impact of surgery on cognitive function: a longitudinal study of middle-aged Danish twins.

PURPOSE: To examine the association between exposure to surgery and 10-year change in cognitive functioning. METHODS: Among 2351 middle-aged twins, a 10-year change in composite cognitive scores derived from five cognitive tests was compared between 903 (38%) twins exposed to surgery classified as major, minor, knee and hip replacement, and other, and a reference group of 1448 (62%) twins without surgery, using linear regression models adjusted for socioeconomic factors. Genetic and shared environmental confounding was addressed in intrapair analyses of 48 monozygotic and 74 dizygotic same-sexed twin pairs. RESULTS: In individual-level analyses, twins with major surgery (mean difference, -0.37; 95% CI, -0.76 to 0.02) or knee and hip replacement surgery (mean difference, -0.54; 95% CI, -1.30 to 0.22) had a tendency of a negligibly higher rate of decline in cognitive score than the reference group. In the intrapair analyses, the surgery-exposed twin had a higher rate of cognitive decline than the co-twin in 55% (95% CI, 45% to 63%) of the pairs. The mean difference in cognitive decline within pairs was -0.21 (95% CI, -0.81 to 0.39). CONCLUSIONS: No significant associations were found between exposure to surgery and change in cognitive score either in individual-level or in intrapair analyses.

Cognitive Functioning after Surgery in Middle-aged and Elderly Danish Twins.

BACKGROUND: Postoperative cognitive dysfunction is common, but it remains unclear whether there are long-term adverse cognitive effects of surgery combined with anesthesia. The authors examined the association between exposure to surgery and level of cognitive functioning in a sample of 8,503 middle-aged and elderly twins. METHODS: Results from five cognitive tests were compared in twins exposed to surgery, classified as major, minor, hip and knee replacement, or other, with those of a reference group without surgery using linear regression adjusted for sex and age. Genetic and shared environmental confounding was addressed in intrapair analyses of 87 monozygotic and 124 dizygotic same-sexed twin pairs in whom one had a history of major surgery and the other did not. RESULTS: Statistically significantly lower composite cognitive score was found in twins with at least one major surgery compared with the reference group (mean difference, -0.27; 95% CI, -0.48 to -0.06), corresponding to one tenth of an SD, that is, a negligible effect size. In the intrapair analysis, the surgery-exposed co-twin had the lower cognitive score in 49% (95% CI, 42 to 56%) of the pairs. None of the other groups differed from the reference group except the knee and hip replacement group that tended to have higher cognitive scores (mean difference, 0.35; 95% CI, -0.18 to 0.87). CONCLUSIONS: A history of major surgery was associated with a negligibly lower level of cognitive functioning. The supplementary analyses suggest that preoperative cognitive functioning and underlying diseases were more important for cognitive functioning in mid- and late life than surgery and anesthesia.

The association between social position and self-rated health in 10 deprived neighbourhoods.

BACKGROUND: A number of studies have shown that poor self-rated health is more prevalent among people in poor, socially disadvantaged positions. The aim of the present study was to investigate the association between self-rated health and social position in 10 deprived neighbourhoods. METHODS: A stratified random sample of 7,934 households was selected. Of these, 641 were excluded from the study because the residents had moved, died, or were otherwise unavailable. Of the net sample of 7,293 individuals, 1,464 refused to participate, 885 were not at home, and 373 did not participate for other reasons, resulting in an average response rate of 62.7%. Multiple logistic regression models were used to estimate the associations between the number of life resources and the odds of self-rated health and also between the type of neighbourhood and the odds of self-rated health. RESULTS: The analysis shows that the number of life resources is significantly associated with having poor/very poor self-rated health for both genders. The results clearly suggest that the more life resources that an individual has, the lower the risk is of that individual reporting poor/very poor health. CONCLUSIONS: The results show a strong association between residents' number of life resources and their self-rated health. In particular, residents in deprived rural neighbourhoods have much better self-rated health than do residents in deprived urban neighbourhoods, but further studies are needed to explain these urban/rural differences and to determine how they influence health.

Self-rated health, ethnicity and social position in a deprived neighbourhood in Denmark.

BACKGROUND: In recent years the close connection between SES and differences in health between ethnic groups have been subject to growing interest among researchers, and some studies have found an association between ethnicity and long term illness and poor health. However, there is limited research-based knowledge about health and illness in ethnic groups in Denmark and about ethnic Danes living in deprived neighbourhoods. The purpose of this study is to investigate associations between self-rated health and ethnicity and social position in a deprived neighbourhood in Denmark in which a relatively largely proportion of the residents are immigrants. METHODS: This study investigates the association between self-rated health used as dependent variable and ethnicity and social position (defined as index for life resources) as the independent variables. The analyses are based on data collected in a survey in a geographically bounded and social deprived neighbourhood, Korskaerparken, located in the municipality of Fredericia in Denmark. The sample consisted of 31% of the residents in Korskaerparken and of these 29% have an ethnic background other than Danish.The analyses were conducted using logistic regression adjusting for confounding variables. RESULTS: This study indicates no significant association between ethnicity and having poor/very poor self-rated health.On the other hand the study confirms that a strong and significant association between the number of residents' life resources and their self-rated health does indeed exist. The results clearly suggest that the more life resources an individual has, the lower is the risk of that individual reporting poor health. CONCLUSION: The results show a strong association between the residents' number of life resources and their self-rated health. In this study, we were not able to identify any association between ethnicity and self-rated health, i.e. our results suggest that ethnicity does not constitute an explanation to differences in self- rated health.