***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The calibration of serum creatinine values to st and ardized creatinine and the commutability of serum creatinine across surveys are essential to the correct use of National Health and Nutrition Examination Survey ( NHANES ) data for kidney function and for generating estimates of the burden of kidney disease in the United States . STUDY DESIGN Calibration study of serum creatinine in NHANES III ( 1988 - 1994 ) and NHANES 1999 - 2000 , 2001 - 2002 , and 2003 - 2004 to directly compare creatinine measurements from the original surveys with st and ard creatinine measured using an assay traceable to known gold-st and ard methods . We also assessed predictors of differences between methods ( potential interferences ) in this general population . SETTING & PARTICIPANTS The NHANES are ongoing cross-sectional surveys of the civilian noninstitutionalized population of the United States . We selected r and om sample s of approximately 200 stored specimens from persons aged 60 years or older from each survey ( NHANES III , 1999 - 2000 , 2001 - 2002 , and 2003 - 2004 ) . MEASUREMENTS Stored serum specimens from the 4 NHANES surveys were analyzed for serum creatinine by using a Roche enzymatic assay implemented at the Clevel and Clinic Research Laboratory ( CCRL ) . The Roche assay is traceable to gold-st and ard reference methods . The original NHANES serum creatinine values were obtained using the Jaffé method ( kinetic alkaline picrate ) implemented in several different laboratories . RESULTS Overall agreement between the original NHANES values ( Jaffé method ) and CCRL measurements ( Roche enzymatic ) was high , but substantial biases were observed in NHANES III and 1999 - 2000 . No bias was observed in NHANES 2001 - 2002 and 2003 - 2004 . Final calibration equations to correct serum creatinine values in the relevant surveys are provided . Assay differences were independent of sex , race/ethnicity , and bilirubin and triglyceride levels , but weakly related to age and glucose concentration . LIMITATIONS We were not able to examine drift in measurements over time within each survey or directly evaluate freeze-thaw effects . CONCLUSIONS The magnitude of differences in serum creatinine measurements in NHANES III and 1999 - 2000 from st and ard creatinine would result in large differences in estimates of kidney function ( 10 % to 20 % ) . Thus , correction of original creatinine values in NHANES III and 1999 - 2000 is essential , but no correction is needed for NHANES 2001 - 2002 or 2003 - 2004 BACKGROUND African American smokers are more likely to experience  tobacco-related morbidity and mortality than European American smokers , and higher rates of menthol cigarette smoking may contribute to these disparities . METHODS We prospect ively measured cumulative exposure to menthol and nonmenthol cigarettes and smoking cessation behavior ( 1985 - 2000 ) , coronary calcification ( 2000 ) , and 10-year change in pulmonary function ( 1985 - 1995 ) in African American and European American smokers recruited in 1985 for the Coronary Artery Risk Development in Young Adults Study . RESULTS We identified 1535 smokers in 1985 ( 972 menthol and 563 nonmenthol ) ; 89 % of African Americans preferred menthol vs 29 % of European Americans ( P<.001 ) . After adjustment for ethnicity , demographics , and social factors , we found nonsignificant trends in menthol smokers toward lower cessation ( odds ratio [ OR ] , 0.71 ; 95 % confidence interval [ CI ] , 0.49 - 1.02 ; P = .06 ) and recent quit attempt ( OR , 0.77 ; 95 % CI , 0.56 - 1.06 ; P = .11 ) rates and a significant increase in the risk of relapse ( OR , 1.89 ; 95 % CI , 1.17 - 3.05 ; P = .009 ) . Per pack-year of exposure , however , we found no differences from menthol in tobacco-related coronary calcification ( adjusted OR , 1.27 ; 95 % CI , 1.01 - 1.60 for menthol cigarettes and 1.33 ; 95 % CI , 1.06 - 1.68 for nonmenthol cigarettes per 10-pack-year increase ; P = .75 for comparison ) or 10-year pulmonary function decline ( adjusted excess decline in forced expiratory volume in 1 second , 84 mL ; 95 % CI , 32 - 137 for menthol cigarettes and 80 mL ; 95 % CI , 30 - 129 for nonmenthol cigarettes , per 10-pack-year increase ; P = .88 for comparison ) . CONCLUSION Menthol and nonmenthol cigarettes seem to be equally harmful per cigarette smoked in terms of atherosclerosis and pulmonary function decline , but menthol cigarettes may be harder to quit smoking BACKGROUND Menthol cigarettes , preferred by African American smokers , have been conjectured to be harder to quit and to contribute to the excess lung cancer burden among black men in the Unites States . However , data showing an association between smoking menthol cigarettes and increased lung cancer risk compared with smoking nonmenthol cigarettes are limited . The Food and Drug Administration is currently considering whether to ban the sale of menthol cigarettes in the United States . METHODS We conducted a prospect i ve study among 85,806 racially diverse adults enrolled in the Southern Community Cohort Study during March 2002 to September 2009 according to cigarette smoking status , with smokers classified by preference for menthol vs nonmenthol cigarettes .  Among 12,373 smokers who responded to a follow-up question naire , we compared rates of quitting between menthol and nonmenthol smokers . In a nested case-control analysis of 440 incident lung cancer case patients and 2213 matched control subjects , using logistic regression modeling we computed odds ratios ( ORs ) and accompanying 95 % confidence intervals ( CIs ) of lung cancer incidence , and applied Cox proportional hazards modeling to estimate hazard ratios ( HRs ) of lung cancer mortality , according to menthol preference . RESULTS Among both blacks and whites , menthol smokers reported smoking fewer cigarettes per day ; an average of 1.6 ( 95 % CI = 1.3 to 2.0 ) fewer for blacks and 1.8 ( 95 % CI = 1.3 to 2.3 ) fewer for whites , compared with nonmenthol smokers . During an average of 4.3 years of follow-up , 21 % of participants smoking at baseline had quit , with menthol and nonmenthol smokers having equal odds of quitting ( OR = 1.02 , 95 % CI = 0.89 to 1.16 ) . A lower lung cancer incidence was noted in menthol vs nonmenthol smokers ( for smokers of < 10 , 10 - 19 , and ≥ 20 cigarettes per day , compared with never smokers , OR = 5.0 vs 10.3 , 8.7 vs 12.9 , and 12.2 vs 21.1 , respectively ) . These trends were mirrored for lung cancer mortality . In multivariable analyses adjusted for pack-years of smoking , menthol cigarettes were associated with a lower lung cancer incidence ( OR = 0.65 , 95 % CI = 0.47 to 0.90 ) and mortality ( hazard ratio of mortality = 0.69 , 95 % CI = 0.49 to 0.95 ) than nonmenthol cigarettes . CONCLUSIONS The findings suggest that menthol cigarettes are no more , and perhaps less , harmful than nonmenthol cigarettes BACKGROUND African Americans have higher tobacco-related morbidity and mortality and are more likely to smoke menthol cigarettes than their white counterparts . This study examined differences between African American menthol and non-menthol smokers in smoking characteristics and cessation . METHODS The study sample consisted of 600 African American smokers enrolled in a clinical trial that assessed the efficacy of sustained-release bupropion for smoking cessation .  Menthol ( n = 471 ) and non-menthol ( n = 129 ) smokers were compared on smoking-related characteristics and abstinence rates at 6 weeks and 6 months . RESULTS  Menthol  smokers were younger ( 41.2 versus 52.9 years ) , more likely to be female ( 73.7 % versus 56.6 % ) and more likely to smoke their first cigarette within 30 minutes of waking up ( 81.7 % versus 69.8 % ) compared to non-menthol smokers ( all P < 0.01 ) . Cigarette taste ( 50 % versus 40 % , P = 0.054 ) was rated non-significantly higher by menthol smokers . Seven-day point-prevalence abstinence from smoking at 6 weeks were 28 % and 42 % ( P = 0.006 ) and at 6 months were 21 % and 27 % ( P = 0.21 ) for menthol and non-menthol smokers , respectively . At 6 weeks follow-up , stepwise logistic regression revealed that among those younger than 50 years , non-menthol smokers were more likely to quit smoking ( odds ratio = 2.0 ; 95 % CI = 1.03 - 3.95 ) as were those who received bupropion ( odds ratio = 2.12 ; 95 % CI = 1.32 - 3.39 ) . CONCLUSION African American menthol smokers had lower smoking cessation rates after 6 weeks of treatment with bupropion-SR , thereby putting menthol smokers at greater risk from the health effects of smoking . Lower overall cessation rates among African Americans menthol smokers may partially explain ethnic differences in smoking-related disease risks AIMS To determine whether African American light smokers who smoked menthol cigarettes  had lower cessation when treated with nicotine replacement therapy and counseling . DESIGN Data were derived from a clinical trial that assessed the efficacy of 2 mg nicotine gum ( versus placebo ) and counseling ( motivational interviewing counseling versus Health Education ) for smoking cessation among African American light smokers ( smoked < or = 10 cigarettes per day ) . PARTICIPANTS The sample consisted of 755 African American light smokers . MEASUREMENTS The primary outcome variable was verified 7-day point-prevalence smoking cessation at 26 weeks follow-up . Verification was by salivary cotinine . FINDINGS Compared to non-menthol smokers , menthol smokers were younger and less confident to quit smoking ( P = 0.023 ) . At 26 weeks post-r and omization , 7-day verified abstinence rate was significantly lower for menthol smokers ( 11.2 % versus 18.8 % for non-menthol , P = 0.015 ) . CONCLUSIONS Among African American light smokers , use of menthol cigarettes is associated with lower smoking cessation rates . Because the majority of African American smokers use menthol cigarettes , a better underst and ing of the mechanism for this lower quit rate is needed Context Guidelines recommend that laboratories estimate glomerular filtration rate ( GFR ) with equations that use serum creatinine level , age , sex , and ethnicity . St and ardizing creatinine measurements across clinical laboratories should reduce variability in estimated GFR . Contribution Using st and ardized creatinine assays , the authors calibrated serum creatinine levels in 1628 patients whose GFR had been measured by urinary clearance of 125I-iothalamate .  They used these data to derive new equations for estimating GFR and to measure their accuracy . The equations were inaccurate only when kidney function was near-normal . Caution s There was no independent sample of patients for measuring accuracy . Implication s By using this equation and a st and ardized creatinine assay , different laboratories can report estimated GFR more uniformly and accurately . The Editors Chronic kidney disease is a recently recognized public health problem . Current guidelines define chronic kidney disease as kidney damage or a  glomerular filtration rate ( GFR ) less than 60 mL/min per 1.73 m2 for 3 months or more , regardless of cause ( 13 ) . Kidney damage is usually ascertained from markers , such as albuminuria . The GFR can be estimated from serum creatinine concentration and demographic and clinical variables , such as age , sex , ethnicity , and body size . The normal mean value for GFR in healthy young men and women is approximately 130 mL/min per 1.73 m2 and 120 mL/min per 1.73 m2 , respectively , and declines by approximately 1 mL/min per 1.73 m2 per year after 40 years of age ( 4 ) . To facilitate detection of chronic kidney disease , gu 
    Output:
    
In a representative sample of U.S. adults  , menthol cigarette smoking was associated with increased all-cause , cardiovascular and cancer mortality with no differences compared to nonmenthol cigarettes .
In the systematic review , menthol cigarette use was associated with inverse risk of cancer compared to nonmenthol cigarette use with some evidence of an increased risk for cardiovascular disease