Does aluminum exposure affect cognitive function? a comparative cross-sectional study.

OBJECTIVES: This study assessed the cognitive function of aluminum-exposed participants from an alum mining zone, compared them with unexposed subjects, and aimed to elucidate the effect of aluminum exposure on cognition. DESIGN: This was a comparative cross-sectional study. Univariate analyses were used to assess the differences between the aluminum-exposed and unexposed groups. Binary logistic regression models were applied to analyze the effect of aluminum exposure. SETTING: The aluminum-exposed participants were included from an alum mining zone and the unexposed subjects were residents from another district without alum-mine-related factories. PARTICIPANTS: We included 539 aluminum-exposed participants (254 men, 285 women) and 1720 unexposed participants (692 men, 1028 women). RESULTS: The mean cognition score on Mini-Mental State Examination was 21.34 (± 6.81) for aluminum-exposed participants. The exposed group had 6.77 times (95% confidence interval, 5.09-9.00) more risk of cognitive impairment than the unexposed group, after adjusting for age, sex, and educational level. No statistically significant association was found between exposure duration and cognition. CONCLUSIONS: This study demonstrated a significant association between aluminum exposure and lower cognitive function.

Reproductive history and risk of cognitive impairment in elderly women: a cross-sectional study in eastern China.

BACKGROUND: Epidemiological studies suggest that proxies of higher lifetime estrogen exposure are associated with better cognitive function in postmenopausal women, but this has not been found consistently. OBJECTIVE: To determine whether reproductive history, an important modifier of estrogen exposure across the lifetime, is associated with risk of cognitive impairment in postmenopausal women. METHODS: We analyzed the baseline data from Zhejiang Major Public Health Surveillance Program (ZPHS) including 4,796 postmenopausal women. Cognitive impairment was assessed through the application of Mini-Mental State Examination questionnaire. Logistic regression models, controlled for an extensive range of potential confounders, were generated to examine the associations between women's reproductive history and risk of cognitive impairment in their later life. RESULTS: The length of reproductive period was inversely associated with risk of cognitive impairment (p = 0.001). Odds ratio (OR) of cognitive impairment were 1.316 (95% CI 1.095∼1.582) for women with 5 or more times of full-term pregnancies, compared with those with 1∼4 times of full-term pregnancies. Women without incomplete pregnancy had a significant higher risk of cognitive impairment (OR = 1.194, 95% CI 1.000∼1.429), compared with the reference (1∼2 times of incomplete pregnancies). Oral contraceptive use (OR = 0.489, 95% CI 0.263∼0.910) and intrauterine device (IUD) use (OR = 0.684, 95% CI 0.575∼0.815) were associated with significantly reduced risk of cognitive impairment. CONCLUSION: Our results indicated that shorter reproductive period, higher number of full-term pregnancies and no incomplete pregnancy history were associated with an increased risk of cognitive impairment. In contrast, oral contraceptive and IUD use corresponded to reduced risk of cognitive impairment.