Proteinuria is associated with persistence of antibody to streptococcal M protein in Aboriginal Australians.
Aboriginal communities in Northern Australia with high rates of group A streptococcal (GAS) skin infection in childhood also have high rates of renal failure in adult life. In a cross-sectional study of one such high risk community, albuminuria was used as a marker of renal disease. The prevalence of albuminuria increased from 0/52 in subjects aged 10-19 years to 10/29 (32.9%) in those aged 50 or more (P < 0.001). Antibodies to streptococcal M protein, markers of past GAS infection, were present in 48/52 (92%) at ages 10-19 years, 16/32 (50%) at ages 30-39, and 20/29 (69%) in those aged 50 or more. After allowing for the age-dependencies of albuminuria and of M protein antibodies (P < 0.001) albuminuria was significantly associated with M protein antibodies (P < 0.01). Thus, 72% of adults aged 30 or more with M protein antibodies also had albuminuria, compared with only 21% of those who were seronegative. More detailed modelling suggested that although most Aboriginal people in this community developed M protein antibodies following GAS infection in childhood, the development of proteinuria was associated with the persistence of such seropositivity into adult life. The models predicted that proteinuria developed at a mean age of 30 years in seropositive persons, at 45 years in seronegative persons who were overweight, and at 62 years in seronegative persons of normal weight. We demonstrated a clear association between evidence of childhood GAS infection and individual risk of proteinuria in adult life. This study provided a strong rationale for prevention of renal disease through the more effective control of GAS skin infections in childhood and through the prevention of obesity in adult life.
Goodfellow
A M
AM
Menzies School of Health Research, Casuarina NT, Australia.
Hoy
W E
WE
Sriprakash
K S
KS
Daly
M J
MJ
Reeve
M P
MP
Mathews
J D
JD
D000293:Adolescent; D000328:Adult; D000419:Albuminuria / Q000276:immunology* / Q000382:microbiology*; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D002648:Child; D064211:Connectin; D003430:Cross-Sectional Studies; D019353:Endemic Diseases / Q000706:statistics & numerical data*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000382:microbiology*; D008875:Middle Aged; D009124:Muscle Proteins; D009194:Myeloma Proteins; D015876:Northern Territory; D009765:Obesity / Q000150:complications; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D013290:Streptococcal Infections / Q000150:complications*; D013297:Streptococcus pyogenes / Q000276:immunology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D064211:Connectin; D009124:Muscle Proteins; D009194:Myeloma Proteins; C085016:multiple myeloma M-proteins; C014689:streptococcal M protein