9 year-olds for women (2 = 4.95, df = 1, P = .026), but there were no sex differences. On the basis of standardized estimates, there were no SC144 msds differences in the prevalence of either subtype between Whites (2.1 , 1.8?.4 for aMCI and 3.8 , 3.4?.2 for naMCI) and Chinese (1.8 , 1.1?.5 for aMCI andPLOS ONE | DOI:10.1371/journal.pone.0142388 November 5,9 /Mild Cognitive Impairment InternationallyFig 2. Crude prevalence estimates of mild cognitive impairment (MCI) among men and women of different age groups. Error bars indicate upper jasp.12117 limits of 95 confidence intervals. Asterisks indicate a significant difference from: * 60?9 years; ** 70?9 years. There were no significant differences between men and women of the same age group for any classification approach. The objective cognitive impairment criteria for the classifications was performance in the bottom 6.681 of qhw.v5i4.5120 the relevant study for at least one harmonized cognitive domain (mild cognitive impairment), a Clinical Dementia Rating (CDR) of 0.5, or a Mini-Mental State Examination (MMSE) score 24?7. doi:10.1371/journal.pone.0142388.g3.6 , 2.6?.6 for naMCI; 2 = 0.19, df = 1, P = .663 and 2 = 0.39, df = 1, P = .532, respectively).order AZD4547 Education and MCICompared to the lowest level (not having completed high school), all higher levels of education conveyed a reduced likelihood of MCI. The odds ratios were 0.58 (P < .001) for having completed high school, 0.55 (P < .001) for technical college or a diploma, and 0.73 (P = .002) for a university degree (S18 Table). Controlling for education however only partially reduced variation in prevalence across studies (further described in S2 Text).Effects of age on subjective memory complaints, functional independence, and objective cognitive impairmentWe conducted supplementary analyses to determine the extent to which effects of age on the harmonized variables used to classify MCI may have contributed to our finding that thePLOS ONE | DOI:10.1371/journal.pone.0142388 November 5,10 /Mild Cognitive Impairment Internationallyprevalence of MCI increased with age (values are detailed in S1 3 Tables). The rate of subjective memory complaints increased with age, from 26.4 among 60?9 year-olds to 30.7 among 70?9 year-olds (2 = 33.95, df = 1, P < .001), and to 37.5 among 80?9 year-olds (2 = 67.58, df = 1, P < .001 vs. 70?9 year-olds). Conversely, the rates of functional independence decreased with age, from 97.7 among 60?9 year-olds to 94.5 among 70?9 year-olds (2 = 112.63, df = 1, P < .001), and to 83.8 among 80?9 year-olds (2 = 480.77, df = 1, P < .001 vs. 70?9 year-olds). There was no significant difference in the rate of objective cognitive impairment between 60?9 year-olds (20.6 ) and 70?9 year-olds (19.5 ; 2 = 1.84, df = 1, P = .175), though the rate was higher for 80?9 year-olds (24.5 ) than for 70?9 year-olds (2 = 30.06, df = 1, P < .001).DiscussionWe analysed pooled data from 11 international cohort studies and found that applying uniform criteria to harmonized data greatly reduced the variation in MCI prevalence internationally. This was the case with each of the three definitions of cognitive impairment that we used to make separate classifications of MCI: performance in the bottom 6.681 , CDR of 0.5, and MMSE score of 24?7. The overall estimates found with these methods were between 6 and 12 , at the lower end of the 3 to 42 range reported by the international studies included in a recent review [14]. Our estimates for the studies contributing to.9 year-olds for women (2 = 4.95, df = 1, P = .026), but there were no sex differences. On the basis of standardized estimates, there were no differences in the prevalence of either subtype between Whites (2.1 , 1.8?.4 for aMCI and 3.8 , 3.4?.2 for naMCI) and Chinese (1.8 , 1.1?.5 for aMCI andPLOS ONE | DOI:10.1371/journal.pone.0142388 November 5,9 /Mild Cognitive Impairment InternationallyFig 2. Crude prevalence estimates of mild cognitive impairment (MCI) among men and women of different age groups. Error bars indicate upper jasp.12117 limits of 95 confidence intervals. Asterisks indicate a significant difference from: * 60?9 years; ** 70?9 years. There were no significant differences between men and women of the same age group for any classification approach. The objective cognitive impairment criteria for the classifications was performance in the bottom 6.681 of qhw.v5i4.5120 the relevant study for at least one harmonized cognitive domain (mild cognitive impairment), a Clinical Dementia Rating (CDR) of 0.5, or a Mini-Mental State Examination (MMSE) score 24?7. doi:10.1371/journal.pone.0142388.g3.6 , 2.6?.6 for naMCI; 2 = 0.19, df = 1, P = .663 and 2 = 0.39, df = 1, P = .532, respectively).Education and MCICompared to the lowest level (not having completed high school), all higher levels of education conveyed a reduced likelihood of MCI. The odds ratios were 0.58 (P < .001) for having completed high school, 0.55 (P < .001) for technical college or a diploma, and 0.73 (P = .002) for a university degree (S18 Table). Controlling for education however only partially reduced variation in prevalence across studies (further described in S2 Text).Effects of age on subjective memory complaints, functional independence, and objective cognitive impairmentWe conducted supplementary analyses to determine the extent to which effects of age on the harmonized variables used to classify MCI may have contributed to our finding that thePLOS ONE | DOI:10.1371/journal.pone.0142388 November 5,10 /Mild Cognitive Impairment Internationallyprevalence of MCI increased with age (values are detailed in S1 3 Tables). The rate of subjective memory complaints increased with age, from 26.4 among 60?9 year-olds to 30.7 among 70?9 year-olds (2 = 33.95, df = 1, P < .001), and to 37.5 among 80?9 year-olds (2 = 67.58, df = 1, P < .001 vs. 70?9 year-olds). Conversely, the rates of functional independence decreased with age, from 97.7 among 60?9 year-olds to 94.5 among 70?9 year-olds (2 = 112.63, df = 1, P < .001), and to 83.8 among 80?9 year-olds (2 = 480.77, df = 1, P < .001 vs. 70?9 year-olds). There was no significant difference in the rate of objective cognitive impairment between 60?9 year-olds (20.6 ) and 70?9 year-olds (19.5 ; 2 = 1.84, df = 1, P = .175), though the rate was higher for 80?9 year-olds (24.5 ) than for 70?9 year-olds (2 = 30.06, df = 1, P < .001).DiscussionWe analysed pooled data from 11 international cohort studies and found that applying uniform criteria to harmonized data greatly reduced the variation in MCI prevalence internationally. This was the case with each of the three definitions of cognitive impairment that we used to make separate classifications of MCI: performance in the bottom 6.681 , CDR of 0.5, and MMSE score of 24?7. The overall estimates found with these methods were between 6 and 12 , at the lower end of the 3 to 42 range reported by the international studies included in a recent review [14]. Our estimates for the studies contributing to.
