Risk Factors for Cognitive Decline

Cognitive impairment is one of the major symptoms of dementia. The main cognitive functions acc orientation to time and place, recall and memory, attention, language, calculation, and visual construction. Impairment of cognitive functions influences the ability of an individual to live independently, and it diminishes the quality of life. In addition to the consequences for an individual, cognitive impairment imposes a major burden on the health care system because it induces an increased risk of institutionalization and hospitalization. Although cognlttve impairment is a less severe disorder than dementia, it is much more common. In a representative papu lation of subjects over 65 years of age, the prevalence of cognitive impairment was 15.8%, whereas the prevalence of dementia was 4.2%.' The risk of cognitive impairment rises exponentially with age. Therefore, we may expect an increase in the number of people with cognitive impairment in our aging society. At present, there acc a number of medications that can delay the progression of dementia and that can stabilize cognitive function. However, no cure or prevention for these disorders has been found yet. Therefore, it is important to identify modifiable risk factors for cognitive impairment and dementia. If these risk factors can be found, preventive intervention may become feasible

No alignment of cattle along geomagnetic field lines found

This paper presents a study of the body orientation of domestic cattle on free pastures in several European states, based on Google satellite photographs. In sum, 232 herds with 3412 individuals were evaluated. Two independent groups participated in our study and came to the same conclusion that, in contradiction to the recent findings of other researchers, no alignment of the animals and of their herds along geomagnetic field lines could be found. Several possible reasons for this discrepancy should be taken into account: poor quality of Google satellite photographs, difficulties in determining the body axis, selection of herds or animals within herds, lack of blinding in the evaluation, possible subconscious bias, and, most importantly, high sensitivity of the calculated main directions of the Rayleigh vectors to some kind of bias or to some overlooked or ignored confounder. This factor could easily have led to an unsubstantiated positive conclusion about the existence of magnetoreception.Comment: Added electronic supplement with source dat

A prospective study on circulating insulin-like growth factor I (IGF-I), IGF-binding proteins, and cognitive function in the elderly

The objective of this study was to investigate the longitudinal relation between the insulin-like growth factor I (IGF-I)/IGF-binding protein (IGFBP) system and cognitive function. The study population consisted of a sample of 186 healthy participants from the population-based Rotterdam Study, aged 55-80 yr. At baseline, we determined fasting blood levels of free and total IGF-I, IGFBP-1, and IGFBP-3. The 30-point Mini-Mental State Examination (MMSE) was used to assess cognitive impairment at baseline (MMSE score of <26; 6% of the sample) and cognitive decline after, on the average, 1.9 yr of follow-up (drop in MMSE score of >1 point/year; 22% of the sample). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression, with adjustment for age, sex, education, body mass index, and fasting insulin levels. Total IGF-I appeared to be inversely related to cognitive impairment, although not significantly. Higher total IGF-I and the total IGF-I/IGFBP-3 ratio were associated with less cognitive decline (OR per SD increase = 0.65; 95% CI = 0.44-0.95 and OR = 0.59; 95% CI = 0.39-0.87, respectively). No relation was observed between free IGF-I and cognitive decline (OR = 0.99; 95% CI = 0.68-1.44). In conclusion, in this prospective study higher serum total IGF-I levels and higher total IGF-I/IGFBP-3 ratios, but not higher free IGF-I levels, were associated with less cognitive decline over the following 2 yr. Circulating total IGF-I levels may reflect an underlying biological process that influences cognitive decline

Smoking and alcohol consumption in relation to cognitive performance at middle age.

In the elderly, cigarette smoking has been related to reduced cognitive performance and moderate alcohol consumption to increased cognitive performance. It is not clear whether these associations also exist in middle age. The authors examined these relations in a population-based cohort study of 1,927 randomly selected, predominantly middle-aged subjects aged 45-70 years at the time of cognitive testing and living in the Netherlands. From 1995 until 2000, an extensive cognitive battery was administered, and compound scores were calculated. Risk factors had been assessed approximately 5 years previously. Multiple linear regression analyses (in which one unit of the cognitive score = one standard deviation) showed that, after the authors adjusted for age, sex, education, alcohol consumption, and cardiovascular risk factors, current smokers had reduced psychomotor speed (beta = -0.159, 95% confidence interval: -0.071, -0.244; p = 0.0003) and reduced cognitive flexibility (beta = -0.133, 95% confidence interval: -0.035,-0.230; p = 0.008) compared with never smokers. This effect was similar to that of being approximately 4 years older. Alcohol consumption was related to increased speed and better flexibility, especially among women who drank 1-4 alcoholic beverages a day. In conclusion, among middle-aged subjects, current smoking was inversely and alcohol consumption positively related to psychomotor speed and cognitive flexibility. This finding suggests that actions to prevent cognitive decline can be taken in middle age

Nonresponse of secondary respondents in multi-actor surveys: Determinants, consequences, and possible remedies

Multi-actor survey data are highly valuable for answering questions about family relations, but the collection of such data is complicated by nonresponse among secondary (nonresident) respondents. Little is known, however, about the degree to which nonresponse of secondary respondents is selective and about the degree to which selective nonresponse biases substantive findings. Using a large representative survey, we analyze nonresponse of nonresident adult children of primary respondents. Nonresponse appears strongly related to characteristics of the parent–child relationship and to characteristics of both parents and children. Consequences are examined for three dependent variables: children’s attitudes, children’s support giving to parents and children’s well-being. Heckman models, which correct for sample selection bias, show that selective response hardly biases the substantive estimates. keywords: values; intergenerational relations; well-being; non-response; survey methodolog