Higher level of education is associated with better cognitive performance and lower risk of developing dementia. However, the effect of education on cognitive performance varies across different cognitive domains and in different populations. The aim of this study was to determine the relationship between education and performance of different cognitive domains among healthy Malay adults. A total of 53 individuals aged 29 to 77 years participated in a battery of neurophysiological tests consisting of Mini-Mental State Examination, Montreal Cognitive Assessment, digit span, visual reproduction and digit symbol speed test (DSST). Blood test was performed for each participant to obtain their biochemical profile. Educational level was divided into level 1 (PMR), level 2 (SPM), level 3 (STPM), level 4 (Diploma) and level 5 (Degree). Simple linear regression indicated that years of education was positively associated with scores of delayed visual reproduction (b=1.348, p=0.002) and DSST (b=3.257, p=0.012). However, scores of all the tests were not significantly different among different levels of education after controlling for age, gender and blood test profile by ANCOVA. Multiple linear regression analysis showed that MMSE score was associated with red cell distribution width (b=-0.628, p=0.005), age (b=-0.119, p<0.001) and there was interaction between high density lipoprotein (HDL) with age (b=0.047, p<001). MoCA score was associated with age (b=-0.121, p<0.001), gender (male compared to female, b=1.870, p=0.020) and HDL (b=1.681, p=0.047). Age was associated with backward digit span (b=-0098, p<0.001) and immediate visual reproduction (b=-0.348, p<0.001), resp. Delayed visual reproduction was associated with age (b=-0.323, p<0.001) and potassium level (b=-4.471, p=0.016). DSST was associated with age (b=-0.911, p<0.001) and alanine aminotransferase (b=-0.754, p=0.002). The lack of association between educational level and cognitive performance after adjusting for confounders in this study maybe due to multiple factors influencing cognitive performance and further studies with a larger sample size are needed to further identify the factors involved.
Keywords: Cognitive performance; education; healthy Malay adults
ABSTRAK
Tahap pendidikan yang tinggi telah dikaitkan dengan prestasi kognitif yang lebih baik dan risiko perkembangan dementia yang lebih rendah. Namun, kesan pendidikan terhadap prestasi kognitif berbeza antara domain kognitif dan populasi yang berlainan. Kajian ini bertujuan untuk menentukan hubungan antara pendidikan dengan prestasi pada domain kognitif yang berlainan pada individu dewasa Melayu yang sihat. Seramai 53 individu yang berumur antara 29 hingga 77 tahun telah menyertai ujian neuropsikologi yang terdiri daripada Pemeriksaan Keadaan Mental Mini, Penilaian Kognitif Montreal, digit span, penghasilan semula visual dan ujian kelajuan simbol digit (DSST). Tahap pendidikan dibahagikan kepada tahap 1 (PMR), tahap 2 (SPM), tahap 3 (STPM), tahap 4 (Diploma) dan tahap 5 (Ijazah Sarjana Muda). Regresi linear mudah menunjukkan bahawa tahap pendidikan berhubung kait secara positif dengan penghasilan semula visual tertunda (b=1.348, p=0.002) dan DSST (b=3.257, p=0.012). Namun, semua skor ujian menjadi tidak berbeza antara tahap pendidikan yang berbeza selepas mengambil kira kesan konpengasas dengan menggunakan ANCOVA. Regresi linear berganda menunjukkan bahawa skor MMSE berhubung kait dengan lebar taburan sel merah (b=-0.628, p=0.005), umur (b=-0.119, p<0.001) dan interaksi antara lipoprotein ketumpatan tinggi (HDL) dan umur (b=0.047, p<001). MoCA didapati berhubung kait dengan umur (b=-0.121, p<0.001), jantina (lelaki berbanding perempuan, b=1.870, p=0.020) dan HDL (b=1.681, p=0.047). Umur juga berhubung kait dengan digit span ke belakang (b=-0098, P<0.001) dan penghasilan semula visual segera (b=-0.348, p<0.001). Penghasilan semula visual tertunda berhubung kait dengan umur (b=-0.323, p<0.001) dan tahap kalium (b=-4.471, p=0.016). DSST berhubung kait dengan umur (b=-0.911, p<0.001) dan alanin aminotransferase (b=-0.754, p=0.002). Hubungan antara tahap pendidikan dan prestasi kognitif tidak dikesan selepas mengambil kira kesan konpengasas yang mencadangkan bahawa prestasi kognitif mungkin dipengaruhi oleh pelbagai faktor dan kajian lanjut dengan bilangan sampel yang lebih besar diperlukan untuk mengenal pasti faktor ini.