@article {1128, title = {Age and cystatin C in healthy adults: a collaborative study.}, journal = {Nephrol Dial Transplant}, volume = {25}, year = {2010}, month = {2010 Feb}, pages = {463-9}, abstract = {

BACKGROUND: Kidney function declines with age, but a substantial portion of this decline has been attributed to the higher prevalence of risk factors for kidney disease at older ages. The effect of age on kidney function has not been well described in a healthy population across a wide age spectrum.

METHODS: The authors pooled individual-level cross-sectional data from 18 253 persons aged 28-100 years in four studies: the Cardiovascular Health Study; the Health, Aging and Body Composition Study; the Multi-Ethnic Study of Atherosclerosis and the Prevention of Renal and Vascular End-Stage Disease cohort. Kidney function was measured by cystatin C. Clinical risk factors for kidney disease included diabetes, hypertension, obesity, smoking, coronary heart disease, cerebrovascular disease, peripheral arterial disease and heart failure.

RESULTS: Across the age range, there was a strong, non-linear association of age with cystatin C concentration. This association was substantial, even among participants free of clinical risk factors for kidney disease; mean cystatin C levels were 46\% higher in participants 80 and older compared with those <40 years (1.06 versus 0.72 mg/L, P < 0.001). Participants with one or more risk factors had higher cystatin C concentrations for a given age, and the age association was slightly stronger (P < 0.001 for age and risk factor interaction).

CONCLUSIONS: There is a strong, non-linear association of age with kidney function, even in healthy individuals. An important area for research will be to investigate the mechanisms that lead to deterioration of kidney function in apparently healthy persons.

}, keywords = {Adult, Aged, Aged, 80 and over, Cross-Sectional Studies, Cystatin C, Humans, Kidney, Middle Aged, Reference Values}, issn = {1460-2385}, doi = {10.1093/ndt/gfp474}, author = {Odden, Michelle C and Tager, Ira B and Gansevoort, Ron T and Bakker, Stephan J L and Katz, Ronit and Fried, Linda F and Newman, Anne B and Canada, Robert B and Harris, Tamara and Sarnak, Mark J and Siscovick, David and Shlipak, Michael G} } @article {1157, title = {Secondhand smoke, vascular disease, and dementia incidence: findings from the cardiovascular health cognition study.}, journal = {Am J Epidemiol}, volume = {171}, year = {2010}, month = {2010 Feb 01}, pages = {292-302}, abstract = {

Recent studies have found that smoking is associated with an increased risk of dementia, but the effects of secondhand smoke (SHS) on dementia risk are not known to have previously been studied. The authors used Cox proportional hazards marginal structural models to examine the association between self-reported lifetime household SHS exposure and risk of incident dementia over 6 years among 970 US participants in the Cardiovascular Health Cognition Study (performed from 1991 to 1999) who were never smokers and were free of clinical cardiovascular disease (CVD), dementia, and mild cognitive impairment at baseline. In addition, because prior studies have found that SHS is associated with increased risk of CVD and that CVD is associated with increased risk of dementia, the authors tested for interactions between SHS and measures of clinical and subclinical CVD on dementia risk. Moderate (16-25 years) and high (>25 years) SHS exposure levels were not independently associated with dementia risk; however, subjects with >25 years of SHS exposure and >25\% carotid artery stenosis had a 3-fold increase (hazard ratio = 3.00, 95\% confidence interval: 1.03, 9.72) in dementia risk compared with subjects with no/low (0-15 years) SHS exposure and < or =25\% carotid artery stenosis. High lifetime SHS exposure may increase the risk of dementia in elderly with undiagnosed CVD.

}, keywords = {Aged, Dementia, Female, Humans, Incidence, Male, Risk Factors, Tobacco Smoke Pollution, Vascular Diseases}, issn = {1476-6256}, doi = {10.1093/aje/kwp376}, author = {Barnes, Deborah E and Haight, Thaddeus J and Mehta, Kala M and Carlson, Michelle C and Kuller, Lewis H and Tager, Ira B} } @article {1348, title = {Antihypertensive medication use and change in kidney function in elderly adults: a marginal structural model analysis.}, journal = {Int J Biostat}, volume = {7}, year = {2011}, month = {2011}, pages = {Article 34}, abstract = {

BACKGROUND: The evidence for the effectiveness of antihypertensive medication use for slowing decline in kidney function in older persons is sparse. We addressed this research question by the application of novel methods in a marginal structural model.

METHODS: Change in kidney function was measured by two or more measures of cystatin C in 1,576 hypertensive participants in the Cardiovascular Health Study over 7 years of follow-up (1989-1997 in four U.S. communities). The exposure of interest was antihypertensive medication use. We used a novel estimator in a marginal structural model to account for bias due to confounding and informative censoring.

RESULTS: The mean annual decline in eGFR was 2.41 {\textpm} 4.91 mL/min/1.73 m(2). In unadjusted analysis, antihypertensive medication use was not associated with annual change in kidney function. Traditional multivariable regression did not substantially change these estimates. Based on a marginal structural analysis, persons on antihypertensives had slower declines in kidney function; participants had an estimated 0.88 (0.13, 1.63) ml/min/1.73 m(2) per year slower decline in eGFR compared with persons on no treatment. In a model that also accounted for bias due to informative censoring, the estimate for the treatment effect was 2.23 (-0.13, 4.59) ml/min/1.73 m(2) per year slower decline in eGFR.

CONCLUSION: In summary, estimates from a marginal structural model suggested that antihypertensive therapy was associated with preserved kidney function in hypertensive elderly adults. Confirmatory studies may provide power to determine the strength and validity of the findings.

}, keywords = {Aged, Antihypertensive Agents, Cystatin C, Data Interpretation, Statistical, Female, Glomerular Filtration Rate, Humans, Hypertension, Kidney, Longitudinal Studies, Male, Models, Statistical}, issn = {1557-4679}, doi = {10.2202/1557-4679.1320}, author = {Odden, Michelle C and Tager, Ira B and van der Laan, Mark J and Delaney, Joseph A C and Peralta, Carmen A and Katz, Ronit and Sarnak, Mark J and Psaty, Bruce M and Shlipak, Michael G} } @article {5854, title = {Hypertension and low HDL cholesterol were associated with reduced kidney function across the age spectrum: a collaborative study.}, journal = {Ann Epidemiol}, volume = {23}, year = {2013}, month = {2013 Mar}, pages = {106-11}, abstract = {

PURPOSE: To determine if the associations among established risk factors and reduced kidney function vary by age.

METHODS: We pooled cross-sectional data from 14,788 nondiabetics aged 40 to 100 years in 4 studies: Cardiovascular Health Study, Health, Aging, and Body Composition Study, Multi-Ethnic Study of Atherosclerosis, and Prevention of Renal and Vascular End-Stage Disease cohort.

RESULTS: Hypertension and low high-density lipoprotein (HDL) cholesterol were associated with reduced cystatin C-based estimated glomerular filtration rate (eGFR) across the age spectrum. In adjusted analyses, hypertension was associated with a 2.3 (95\% confidence interval [CI], 0.1, 4.4), 5.1 (95\% CI, 4.1, 6.1), and 6.9 (95\%~CI, 3.0, 10.4) mL/min/1.73 m(2) lower eGFR in participants 40 to 59, 60 to 79, and at least 80~years, respectively (P for interaction < .001). The association of low HDL cholesterol with reduced kidney function was also greater in the older age groups: 4.9 (95\% CI, 3.5, 6.3), 7.1 (95\% CI, 6.0, 8.3), 8.9 (95\% CI, 5.4, 11.9) mL/min/1.73 m(2) (P for interaction < .001). Smoking and obesity were associated with reduced kidney function in participants under 80 years. All estimates of the potential population impact of the risk factors were modest.

CONCLUSIONS: Hypertension, obesity, smoking, and low HDL cholesterol are modestly associated with reduced kidney function in nondiabetics. The associations of hypertension and HDL cholesterol with reduced kidney function seem to be stronger in older adults.

}, keywords = {Adult, Age Factors, Aged, Aged, 80 and over, Aging, Causality, Cholesterol, LDL, Cohort Studies, Comorbidity, Cross-Sectional Studies, Cystatin C, Female, Humans, Hypertension, Kidney Function Tests, Male, Netherlands, Obesity, Prevalence, Renal Insufficiency, Chronic, Risk Factors, Smoking, United States}, issn = {1873-2585}, doi = {10.1016/j.annepidem.2012.12.004}, author = {Odden, Michelle C and Tager, Ira B and Gansevoort, Ron T and Bakker, Stephan J L and Fried, Linda F and Newman, Anne B and Katz, Ronit and Satterfield, Suzanne and Harris, Tamara B and Sarnak, Mark J and Siscovick, David and Shlipak, Michael G} }