***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: The purpose of this study was to evaluate the association of the insulin resistance syndrome with both blood pressure and target organ damage in blacks and whites with essential hypertension . Eighty-two black and 63 white French Canadian patients were studied . None had diabetes , and antihypertensive medications had been discontinued for ≥1 week . Measurements included 24-hour blood pressure monitoring , fasting plasma lipids , insulin sensitivity determined with the Bergman minimal model , echocardiogram , microalbumin excretion , and inulin and lithium clearances . Compared with the white French Canadians , black patients had an attenuated nighttime reduction in blood pressure ( P < 0.02 ) , increased cardiac dimensions ( P < 0.001 ) , greater microalbumin excretion ( P < 0.05 ) , increased inulin clearance ( indicative of glomerular hyperfiltration;P < 0.001 ) , and decreased lithium clearance ( indicative of increased sodium reabsorption in the proximal tubule;P < 0.001 ) . Blood pressure levels were not related to insulin resistance ; although in blacks , the nighttime reduction in systolic blood pressure was inversely related to fasting plasma insulin ( r = −0.18 , P < 0.04 ) . In a stepwise multivariate analysis ( including blood pressure levels and components of the insulin resistance syndrome as independent variables ) , race was the strongest predictor of left ventricular mass ( r = 0.53 , P < 0.000 ) , relative wall thickness ( r = 0.49 , P < 0.000 ) , and both inulin ( r = 0.53 , P < 0.000 ) and lithium ( r = 0.41 , P < 0.000 ) clearances . Nighttime systolic blood pressure was also a significant determinant of concentric left ventricular hypertrophy ( r = 0.37 , P < 0.000 ) . In blacks , microalbumin excretion was related to insulin resistance . These observations are consistent with the hypothesis that there is a genetic contribution to cardiac hypertrophy , glomerular hyperfiltration , and sodium retention in blacks with essential hypertension In 38 hospitalized patients with uncomplicated essential hypertension  intra-arterial pressure was recorded continuously for 24 hours with the Oxford technique . On the basis of beat by beat analysis , hourly and 24-hour means of mean arterial pressure ( MAP ) and heart rate ( HR ) were obtained . The st and ard deviations and variation coefficients of the hourly means were used as a measure of absolute and relative blood pressure variability respectively . By r and omization patients were ambulant during the day  ( group A ; n = 19 ) or they were restricted to bed ( group B ) . The patients of group B were sensory deprived during the first 4 hours of the blood pressure recording . During the night MAP , HR , and their respective variabilities were similar for both groups . During bed rest MAP was reduced as compared to ambulant values ( P less than 0.05 ) , but bed rest had no effect on HR , or on the variability of HR and MAP . During concomitant sensory deprivation HR and the variability of MAP and HR all declined to nightly values , though MAP did not change . In group B , HR-variability ( absolute and relative ) was inversely correlated to age , but no relationship between these two parameters was observed in group A. During concomitant sensory deprivation , but not during bed rest alone or during night rest , relative MAP-variability was also inversely correlated to age . It is concluded that sensory stimuli have an important effect on HR and on the variability of MAP and HR , but not on MAP itself , indicating that to some extent blood pressure and its variability are regulated independently A number of studies have shown that a smaller than normal nocturnal blood pressure ( BP ) decrease is associated with cardiovascular disease . However , no large prospect i ve studies have examined the reliability of nocturnal dipping within individuals . The aim of our study was to investigate the short-term variability of nocturnal BP fall in a large cohort of patients with recently diagnosed essential hypertension . In all , 414 uncomplicated never treated hypertensive patients referred to our outpatient hypertension hospital clinic ( mean age 46±12 years ; 257 M , 157 F ) prospect ively underwent : ( 1 ) repeated clinic BP measurements ;  ( 2 ) routine examinations recommended by WHO/ISH guidelines ; and ( 3 ) ambulatory BP monitoring ( ABPM ) twice within a 4-week period .  Dipping pattern was defined as a reduction in the average systolic and diastolic BP at night greater than 10 % compared to average daytime values . Overall , 311 patients ( 75.1 % ) showed no change in their diurnal variations in BP . Of the 278 patients who had a dipping pattern on the first ABPM , 219 ( 78.7 % ) confirmed this type of profile on the second ABPM , while 59 ( 21.3 % ) showed a nondipping pattern . Among 37 dipper patients with > 20 % of nocturnal systolic BP decrease ( extreme dippers ) , only 16 ( 43.2 % ) had this marked fall in BP on the second ABPM . Of the 136 patients who had a nondipping pattern on the first ABPM , 92 ( 67.6 % ) confirmed their initial profile on the second ABPM , while 44 ( 32.4 % ) did not . Patients with reproducible nondipping profile were older ( 48±12 years ) than those with reproducible dipping profile ( 44±12 years , P<0.05 ) . These findings indicate that : ( 1 ) short-term reproducibility of nocturnal fall in BP in untreated middle-aged hypertensives is rather limited : overall , one-fourth of patients changed their initial dipping patterns when they were studied again after a few weeks ; ( 2 ) this was particularly true for extreme dipping and nondipping patterns ; ( 3 ) abnormalities in nocturnal BP fall , assessed by a single ABPM , can not be taken as independent predictors of increased cardiovascular risk We examined the racial differences in left ventricular ( LV ) geometric pattern in relation to 24-hour ambulatory blood pressure ( BP ) monitoring and the presence or absence of a nocturnal BP dip . Our study confirms the blunting of nocturnal BP dip among black hypertensives . Body mass index , rather than race , was a major determinant of left ventricular hypertrophy . We did not observe a difference in prevalence of left ventricular hypertrophy by race . However , left ventricular adaptation to hypertension differed in hypertensive black and white individuals ; whereas most of the white patients with Stage 1 - 2 hypertension had a normal ventricular pattern , LV concentric remodeling and concentric hypertrophy were the most common adaptive ventricular patterns in blacks with Stage 1 - 2 hypertension . A six-fold higher prevalence of concentric remodeling was observed in blacks as compared with whites . The impaired nocturnal BP dip in blacks may contribute to the different hemodynamic pattern . Determinants of myocardial oxygen consumption were significantly higher in black hypertensives 
    Output:
    
Smaller nocturnal blood pressure falls and a higher prevalence of non-dipping may contribute to the higher levels of hypertension complications seen in Black people .