The effect of genetic variants, anthropometry and the environment on lipid profile in adults in Northern Ghana

Simple item page
dc.contributor.authorAgongo, Godfred
dc.date.accessioned2020-10-14T12:55:28Z
dc.date.available2020-10-14T12:55:28Z
dc.date.issued2019
dc.descriptionA thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of PhD in Human Geneticsen_ZA
dc.description.abstractGenetic polymorphisms, environmental factors and gene-environment interactions are associated with variations in lipid levels. This evidence comes from studies in mainly Europeans and people of African descent but little or no data exists on the influence of these factors on lipid levels in indigenous black African populations. The aim of the current study was therefore to characterize the principal environmental and genetic factors that influence serum lipid levels in a rural, adult Ghanaian population and to determine if gene-environment interactions further modulate lipid levels. It was a cross-sectional survey that recruited 2016 men and women resident in the study area and aged 40-60 years. Self-reported socio-demographic and behavioural data were collected using a structured questionnaire. Simple anthropometric measures were taken using standardised procedures and visceral and abdominal subcutaneous adipose tissue thickness were measured using ultrasound. Whole blood was collected for DNA extraction and serum was used for the measurement of total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C) and triglyceride (TG). Genotyping of candidate genes was performed using the H3Africa single nucleotide variant genotyping array. Multivariable linear regression analysis was used to test the association of environmental factors with lipid levels. The effect of genetic polymorphisms and geneenvironment interaction on lipid levels was tested using regression models with Bonferroniadjusted p values. The prevalence of dyslipidaemia among the total population was as follows: low HDL-C: 60.30%, high LDL-C=5.55%, high TC=4.02% and high TG=2.12%. A greater proportion of women had low HDL-C compared to men (p=0.005). Subcutaneous abdominal fat was associated with TC (β=0.067, p=0.015) and TG (β=0.137, p<0.001) among women and LDL-C (β=0.139, p=0.006) and TC (β=0.071, p=0.048) among men. Body mass index was associated with TC (β=0.010, p=0.043) among men while waist circumference was associated with LDL-C (β=0.116, p<0.001) and TG (β=0.094, p<0.001) among women. Hip circumference was negatively associated (β=-0.053, p=0.043), while visceral fat was positively associated with TG (β=0.033, p=0.022) among women. Socioeconomic status, education, being unmarried and employment were associated with HDL-C (β=0.081, p=0.004), LDL-C (β=0.095, p=0.004) and TG (β=0.095, p=0.001) respectively, all among women, and TC (β=0.070, p=0.010) among men. Tobacco smoking (β=0.066, p=0.024) among men and alcohol intake among women (β=0.084, p=0.001) were associated with HDL-C levels. For the genetic association analysis the lead variants for association with HDL-C were rs17231520 (β=0.139, p<0.0001) and rs34065661 (β=0.137, p<0.0001), both in CETP. The interaction between tobacco smoking and ABCA1 (rs10124686) was associated with higher TC levels (p=0.041) while that between CETP (rs34620476) and tobacco smoking was associated with lower TG levels in men (p=0.020). Associations of education, employment and adiposity with lipid levels suggest that future societal advances and increases in the prevalence of obesity may lead to associated adverse health consequences. Variants in CETP strongly modulate HDL-C levels in the study population. Total cholesterol and TG levels may be modestly influenced by gene-environment interactions of ABCA1 and CETP, respectively, with smoking among men in the study population.en_ZA
dc.description.librarianTL (2020)en_ZA
dc.facultyFaculty of Health Sciencesen_ZA
dc.format.extentOnline resource (226 leaves)
dc.identifier.citationAgongo, Godfred (2019) The effect of genetic variants, anthropometry and the environment on lipid profiles in adults in northern Ghana, University of the Witwatersrand, Johannesburg, <http://hdl.handle.net/10539/29842>
dc.identifier.urihttps://hdl.handle.net/10539/29842
dc.language.isoenen_ZA
dc.phd.titlePhDen_ZA
dc.subject.meshPolymorphism (Genetics)
dc.subject.meshAnthropometry
dc.titleThe effect of genetic variants, anthropometry and the environment on lipid profile in adults in Northern Ghanaen_ZA
dc.typeThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
Godfred's PhD thesis_final.pdf
Size:
6.35 MB
Format:
Adobe Portable Document Format
Description:
Main Work
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
ETD Collection