Demographic and Lifestyle Characteristics, but Not Apolipoprotein E Genotype, Are Associated with Intelligence among Young Chinese College Students

<div><p>Background</p><p>Intelligence is an important human feature that strongly affects many life outcomes, including health, life-span, income, educational and occupational attainments. People at all ages differ in their intelligence but the origins of these differences are much debated. A variety of environmental and genetic factors have been reported to be associated with individual intelligence, yet their nature and contribution to intelligence differences have been controversial.</p><p>Objective</p><p>To investigate the contribution of apolipoprotein E (<i>APOE</i>) genotype, which is associated with the risk for Alzheimer’s disease, as well as demographic and lifestyle characteristics, to the variation in intelligence.</p><p>Methods</p><p>A total of 607 Chinese college students aged 18 to 25 years old were included in this prospective observational study. The Chinese revision of Wechsler Adult Intelligence Scale (the fourth edition, short version) was used to determine the intelligence level of participants. Demographic and lifestyle characteristics data were obtained from self-administered questionnaires.</p><p>Results</p><p>No significant association was found between <i>APOE</i> polymorphic alleles and different intelligence quotient (IQ) measures. Interestingly, a portion of demographic and lifestyle characteristics, including age, smoking and sleep quality were significantly associated with different IQ measures.</p><p>Conclusions</p><p>Our findings indicate that demographic features and lifestyle characteristics, but not <i>APOE</i> genotype, are associated with intelligence measures among young Chinese college students. Thus, although <i>APOE</i> ε4 allele is a strong genetic risk factor for Alzheimer’s disease, it does not seem to impact intelligence at young ages.</p></div

Linkage disequilibrium between SNPs in controls as measured by pairwise r² values.

<p>Values are given as percentages out of a maximum of 100. Solid black boxes indicate an r² value of 100.</p

Associations between <i>APOE</i> ε4 and IQ score measures.

<p>Regression coefficients, 95% CIs, and p values were calculated from linear regression models. Regression coefficients are interpreted as the difference in means of the given IQ measure between carriers and non-carriers of the ε4 allele (i.e. ε4 allele present vs. ε4 allele not present). A regression coefficient greater than “0” indicates a higher value of the given measure for ε4 carriers, and a regression coefficient less than “0” indicates a lower value of the given measure for ε4 carriers. Multivariable models were adjusted for school (Xiamen University or AnFang College), age, gender, height, weight, BMI, personality, smoking, drinking alcohol, physical exercise, and sleep quality. P values of 0.01 or lower were considered as statistically significant after applying a Bonferroni correction for multiple testing. Min = Minimum; Q1 = first quartile; Q3 = third quartile; Max = Maximum; CI = confidence interval.</p><p>Associations between <i>APOE</i> ε4 and IQ score measures.</p

Associations of subject demographic and lifestyle characteristics with IQ score measures (PSI and PRI) from multivariable analysis.

<p>Regression coefficients, 95% CIs, and p values were calculated from multivariable linear regression models. Regression coefficients are interpreted as the change in the mean IQ measure corresponding to the increase specified in parenthesis (continuous variables) or presence of the given characteristic (categorical variables). For all variables except height, weight, and BMI, models were adjusted for age, gender, height, weight, BMI, personality, smoking, alcohol consumption, physical exercise, and sleep quality. For height, weight, and BMI, models were adjusted for age, gender, personality, smoking, alcohol consumption, physical exercise, and sleep quality. P values of 0.005 or lower were considered as statistically significant after applying a Bonferroni correction for multiple testing. CI = confidence interval.</p><p>Associations of subject demographic and lifestyle characteristics with IQ score measures (PSI and PRI) from multivariable analysis.</p

Associations between <i>APOE</i> ε2 and IQ score measures.

<p>Regression coefficients, 95% CIs, and p values were calculated from linear regression models. Regression coefficients are interpreted as the difference in means of the given IQ measure between carriers and non-carriers of the ε2 allele (i.e. ε2 allele present vs. ε2 allele not present). A regression coefficient greater than “0” indicates a higher value of the given measure for ε2 carriers, and a regression coefficient less than “0” indicates a lower value of the given measure for ε2 carriers. Multivariable models were adjusted for school (Xiamen University or AnFang College), age, gender, height, weight, BMI, personality, smoking, drinking alcohol, physical exercise, and sleep quality. P values of 0.01 or lower were considered as statistically significant after applying a Bonferroni correction for multiple testing. Min = Minimum; Q1 = first quartile; Q3 = third quartile; Max = Maximum; CI = confidence interval.</p><p>Associations between <i>APOE</i> ε2 and IQ score measures.</p

Single SNP associations with PD.

<p>PD = Parkinson's disease. SNP = single nucleotide polymorphism. MA = minor allele. OR = odds ratio. CI = confidence interval. *Chromosomal positions based on the February 2009 (GRCH37/hg19) genome assembly [<i>SNCA</i> is located at Chr4;90,645,251–90,759,447]. ORs, 95% CIs, and p-values result from logistic regression models adjusted for age and gender. ORs correspond to presence vs. absence of the minor allele.</p

Associations of subject demographic and lifestyle characteristics with IQ score measures (Full Scale IQ Score, VCI, and WMI) from multivariable analysis.

<p>Regression coefficients, 95% CIs, and p values were calculated from multivariable linear regression models. Regression coefficients are interpreted as the change in the mean IQ measure corresponding to the increase specified in parenthesis (continuous variables) or presence of the given characteristic (categorical variables). For all variables except height, weight, and BMI, models were adjusted for age, gender, height, weight, BMI, personality, smoking, alcohol consumption, physical exercise, and sleep quality. For height, weight, and BMI, models were adjusted for age, gender, personality, smoking, alcohol consumption, physical exercise, and sleep quality. P values of 0.005 or lower were considered as statistically significant after applying a Bonferroni correction for multiple testing. CI = confidence interval.</p><p>Associations of subject demographic and lifestyle characteristics with IQ score measures (Full Scale IQ Score, VCI, and WMI) from multivariable analysis.</p

Bilateral small chronic infarcts and patchy and confluent areas of leukoaraiosis seen on fluid attenuated inversion recovery (FLAIR) MRI on patient with NOTCH3 p.R558C mutation.

<p>Bilateral small chronic infarcts and patchy and confluent areas of leukoaraiosis seen on fluid attenuated inversion recovery (FLAIR) MRI on patient with NOTCH3 p.R558C mutation.</p

Exonic Re-Sequencing of the Chromosome 2q24.3 Parkinson’s Disease Locus

<div><p>Genome-wide association studies (GWAS) in Parkinson’s disease (PD) have identified over 20 genomic regions associated with disease risk. Many of these loci include several candidate genes making it difficult to pinpoint the causal gene. The locus on chromosome 2q24.3 encompasses three genes: <i>B3GALT1</i>, <i>STK39</i>, and <i>CERS6</i>. In order to identify if the causal variants are simple missense changes, we sequenced all 31 exons of these three genes in 187 patients with PD. We identified 13 exonic variants including four non-synonymous and three insertion/deletion variants (indels). These non-synonymous variants and rs2102808, the GWAS tag SNP, were genotyped in three independent series consisting of a total of 1976 patients and 1596 controls. Our results show that the seven identified 2q24.3 coding variants are not independently responsible for the GWAS association signal at the locus; however, there is a haplotype, which contains both rs2102808 and a <i>STK39</i> exon 1 6bp indel variant, that is significantly associated with PD risk (Odds Ratio [OR] = 1.35, 95% CI: 1.11–1.64, P = 0.003). This haplotype is more associated than each of the two variants independently (OR = 1.23, P = 0.005 and 1.10, P = 0.10, respectively). Our findings suggest that the risk variant is likely located in a non-coding region. Additional sequencing of the locus including promoter and regulatory regions will be needed to pinpoint the association at this locus that leads to an increased risk to PD.</p></div

Representative immunostaining showing examples of prostate tumors with (A) 0–25% staining percentage, (B) 26–50% staining percentage, (C) 51–75% staining percentage, and (D) 76–100% staining percentage.

<p>Representative immunostaining showing examples of prostate tumors with (A) 0–25% staining percentage, (B) 26–50% staining percentage, (C) 51–75% staining percentage, and (D) 76–100% staining percentage.</p