Association between low density lipoprotein and rheumatoid arthritis genetic factors with low density lipoprotein levels in rheumatoid arthritis and non-rheumatoid arthritis controls.
OBJECTIVES
While genetic determinants of low density lipoprotein (LDL) cholesterol levels are well characterised in the general population, they are understudied in rheumatoid arthritis (RA). Our objective was to determine the association of established LDL and RA genetic alleles with LDL levels in RA cases compared with non-RA controls.


METHODS
Using data from electronic medical records, we linked validated RA cases and non-RA controls to discarded blood samples. For each individual, we extracted data on: first LDL measurement, age, gender and year of LDL measurement. We genotyped subjects for 11 LDL and 44 non-HLA RA alleles, and calculated RA and LDL genetic risk scores (GRS). We tested the association between each GRS and LDL level using multivariate linear regression models adjusted for age, gender, year of LDL measurement and RA status.


RESULTS
Among 567 RA cases and 979 controls, 80% were female and mean age at the first LDL measurement was 55 years. RA cases had significantly lower mean LDL levels than controls (117.2 vs 125.6 mg/dl, respectively, p<0.0001). Each unit increase in LDL GRS was associated with 0.8 mg/dl higher LDL levels in both RA cases and controls (p=3.0×10(-7)). Each unit increase in RA GRS was associated with 4.3 mg/dl lower LDL levels in both groups (p=0.01).


CONCLUSIONS
LDL alleles were associated with higher LDL levels in RA. RA alleles were associated with lower LDL levels in both RA cases and controls. As RA cases carry more RA alleles, these findings suggest a genetic basis for epidemiological observations of lower LDL levels in RA.
['Liao|Katherine P|KP|', 'Diogo|Dorothée|D|', 'Cui|Jing|J|', 'Cai|Tianxi|T|', 'Okada|Yukinori|Y|', 'Gainer|Vivian S|VS|', 'Murphy|Shawn N|SN|', 'Gupta|Namrata|N|', 'Mirel|Daniel|D|', 'Ananthakrishnan|Ashwin N|AN|', 'Szolovits|Peter|P|', 'Shaw|Stanley Y|SY|', 'Raychaudhuri|Soumya|S|', 'Churchill|Susanne|S|', 'Kohane|Isaac|I|', 'Karlson|Elizabeth W|EW|', 'Plenge|Robert M|RM|']
D000328:Adult D000368:Aged D001172:Arthritis, Rheumatoid D016022:Case-Control Studies D050171:Dyslipidemias D005260:Female D020022:Genetic Predisposition to Disease D005838:Genotype D006801:Humans D008077:Lipoproteins, LDL D008297:Male D008875:Middle Aged D020641:Polymorphism, Single Nucleotide
Rheumatoid Arthritis Gene Polymorphism Lipids