To the best of our knowledge, the presented results are the first estimates of the cognitive function and its associations with various cardiovascular risk factors in a large group of general middle-aged and elderly urban population in Lithuania that were obtained using internationally accepted battery of five standard tasks. This study confirmed the association between older age, lower education level and poorer cognitive performance which had been proposed by previous studies
]. Some gender differences were ascertained as well. In general, women performed marginally better than men on the global cognitive score, conversely to other studies in such countries as Taiwan, Egypt, India or China
]. These results can differ because of high educational level of Lithuanian women. In our study, women performed better on immediate and delayed verbal recall than men. These findings are similar to those of the previous large longitudinal study carried out in Netherlands
]. Besides, most studies confirm that women have advantages in memory tasks compared to men
The results of this study indicate that links between cardiovascular risk factors and cognitive function are mixed and highly dependent on gender. Stroke was an independent predictor for lowered cognitive function. This finding supports the results published in by other studies
]. The previous study suggests association between coronary heart disease history and poorer cognitive scores
]. In the current study IHD also showed a statistically significant association with lowered cognitive function but among men only. This finding could be explained by higher rates of cardiovascular disease among men in Lithuania
]. It was suggested that cardiovascular risk factors and diabetes, may also be linked with lowered cognitive function
]. But the current research similarly to some other studies found no consistent associations
]. Metabolic syndrome was not related to poorer cognitive function as well. Researchers in other studies came to a conclusion that association between cognition, metabolic syndrome and its components depends on the specific areas of cognition, which were not analyzed in this study
In contrast to the research which reported that hypertension was associated with decreased cognitive function and blood pressure was not
], we found opposite results. In general, the previous findings suggest very uncertain connections between hypertension and cognition
]. Biomarkers were differently associated with lowered cognitive function. Moreover, these associations were confirmed only in univariate analyses. Which biomarkers are related to cognition remains a controversial issue
]. Surprisingly, risk behaviors such as smoking and alcohol drinking were not related to lowered cognition differently from the findings in the previous studies
]. However, physical activity was associated with better cognitive performance among women, but not among men.
It had been argued that depressive symptoms regulate association between cognitive functioning and cardiovascular risk factors
], yet our results indicated that the relation between depressive symptoms and lowered cognitive function was confirmed only in univariate analysis. The implication is that cardiovascular risk factors affect cognition independently. Besides, self-rated quality of life in elderly is influenced by a poorer cognitive function
]. The current investigation revealed that a poor quality of life was the most important predictor of a lowered cognitive function.
Limitations of our findings include the absence of additional cognitive measures such as MMSE which allowed us determine the prevalence of an impaired cognitive function using the standard criteria and compare the prevalence in other populations. Dementia status was not controlled in our research as well. Other limitations of our study include assessment of cognitive function by random sample in Kaunas population, but not on a nationally based measure. Additionally, we used a cross-sectional design despite the HAPIEE study is planned as cohort study. Although incremental models were not analyzed in this research, interactions of possible confounders will be discussed in future studies.
Despite some limitations of the study it is the first population based study in Lithuania which analyzed associations between cognitive ability and various CVD risk factors. This study reflects on biopsychosocial model of health by analyzing cognitive functions in respect to many different factors including clinical data as biomarkers, self-report measurements as depressive symptoms and socio-demographic data.