Risk factors for prehypertension in the community: a prospective analysis from the Western New York Health Study

BACKGROUND AND AIM

Prehypertension is an increasingly highly prevalent condition in the general population, and is associated with an increased risk for coronary heart disease and stroke. However, evidence from population-based studies of the risk factors for prehypertension is scant. We sought to examine the predictors of progression from normotension to prehypertension in a community-based population from Western New York.

METHODS AND RESULTS

A longitudinal analysis, over 6 years of follow-up, among 569 men and women (mean age 51.8 years) who were free of prehypertension, hypertension, cardiovascular disease and diabetes at the baseline examination, in the Western New York Health Study (WNYHS). Incident prehypertension at follow-up was defined as systolic blood pressure of 120-139 mm Hg and/or diastolic blood pressure of 80-89 mm Hg. The cumulative six year incidence of prehypertension was 33.5% (189/564). In bivariate analyses, there were several correlates of incident prehypertension, including age, BMI and waist circumference, impaired fasting glucose (IFG), uric acid, and baseline blood pressure levels. After multivariate adjustment, IFG at baseline [odds ratio (OR): 1.70, 95% CI: 1.07-2.69) and weight gain since age 25 (OR: 1.12, 1.04-1.21 per 10 lb increase)] were the strongest significant predictors of prehypertension at follow-up. Neither baseline waist circumference nor change in BMI were predictor variables in models when they were substituted for weight gain.

CONCLUSIONS

Results from this study suggest early dysregulation of glucose metabolism and weight gain over the lifespan may represent important risk factors for prehypertension in the general population.

Polychlorinated biphenyl serum concentrations, lifestyle and time-to-pregnancy

BACKGROUND

Consumption of fish contaminated with polychlorinated biphenyls (PCBs) and prenatal PCB serum concentrations have been associated with a longer time-to-pregnancy (TTP). However, the relationship between preconception serum PCBs concentrations and TTP has not been previously studied.

METHODS

Eighty-three women (contributing 442 menstrual cycles) planning pregnancies completed daily diaries regarding menstruation, intercourse, home pregnancy test results, and reported use of alcohol and cigarettes. TTP denoted the number of observed menstrual cycles required for pregnancy. Preconception blood specimens underwent toxicologic analysis for 76 PCB congeners via gas chromatography with electron capture; serum lipids were quantified with enzymatic methods. A priori, PCB congeners were summed into a total and three groupings-estrogenic, anti-estrogenic and other-and entered into discrete analogs of Cox models with time-varying covariates to estimate fecundability odds ratios (FOR) and corresponding 95% confidence intervals (CIs).

RESULTS

Estrogenic and anti-estrogenic PCB concentrations (ng/g serum) conferred reduced FORs in fully adjusted models (0.32; 95% CI 0.03, 3.90 and 0.01: 95% CI < 0.00, 1.99, respectively). Reduced FORs (0.96) were observed for alcohol consumption standardized to a 28-day menstrual cycle in the same adjusted model (FOR = 0.96; 95% CI 0.93, 1.00).

CONCLUSIONS

These data suggest that environmental exposures including those amenable to change, such as alcohol consumption, may impact female fecundity. The findings are sensitive to model specification and PCB groupings, underscoring the need to further assess the impact of chemical mixtures on sensitive reproductive outcomes, such as TTP, especially in the context of lifestyle factors which are amenable to change, thereby improving reproductive health.

The utility of neural network in the diagnosis of Cheyne-Stokes respiration

The aim of this study was to design a diagnostic model to identify patients with Cheyne-Stokes respiration (CSR-CSA) based on indices of oximetric spectral analysis. A retrospective analysis of oximetric recordings of 213 sleep studies conducted over a one-year period at a Veterans Affairs medical facility was performed. A probabilistic neural network (PNN) was developed from salient features of the oximetric spectral analysis, desaturation events and the delta index. A fivefold cross-validation was used to assess the accuracy of the neural network in identifying CSR-CSA. When compared to overnight polysomnography, the PNN achieved a sensitivity of 100% (95% confidence interval [CI] 85%-100%) and a specificity of 99% (95% 97%-100%) with a corresponding area under the curve of 99% (95% CI 99%-100%). When combined with overnight pulse oximetry, PNN offers an accurate and easily applicable tool to detect CSR-CSA.

Early computed tomography hypodensity predicts hemorrhage after intravenous tissue plasminogen activator in acute ischemic stroke

Parenchymal hypodensity is a proposed risk factor for hemorrhage after recombinant tissue plasminogen activator (TPA) thrombolysis for ischemic stroke. In Buffalo, NY, and Houston, TX, the authors reviewed 70 patients who were treated with intravenous TPA for acute middle cerebral artery (MCA) stroke. Two observers blinded to clinical outcome analyzed initial noncontrast head computed tomography (CT) scans. Basal ganglia CT hypodensity was quantitated in Hounsfield units (HUs). Contralateral-ipsilateral difference in density was calculated using the asymptomatic side as a control. Ictus time to TPA averaged 2.5 hours. Six patients developed symptomatic intraparenchymal hematomas (2 fatal). The hemorrhage group had more severe basal ganglia hypodensity (mean 7.5 +/- 1.4, range 6-10 HU) than the nonhemorrhage group (2.2 +/- 1.4, range 0-9 HU) (P < .0001). The hemorrhage group had hypodensity of > 5 HU; the nonhemorrhage group had hypodensity of < or = 4 HU, except 1 patient with hypodensity of 9 HU. In predicting hemorrhage, the positive predictive value of hypodensity > 5 HU was 86%; the negative predictive value was 100%. Prethrombolysis NIH Stroke Scale (NIHSS) deficit (P = .0007) and blood glucose (P = .005) were also higher in the hemorrhage group. Age, gender, smoking, hypertension, and ictus time to TPA infusion did not differ between the 2 groups. Logistic regression indicated that basal ganglia hypodensity was the best single predictor of hemorrhage. Hypodensity and NIHSS score together predicted all cases of hemorrhage. The authors conclude that basal ganglia hypodensity quantified by CT may be a useful method of risk stratification to select acute MCA stroke patients for thrombolytic therapy.

Gray matter T2 hypointensity is related to plaques and atrophy in the brains of multiple sclerosis patients

Cortical and subcortical gray matter hypointensities on T2-weighted MR images (T2WI) occur commonly in MS brains and have been related to disease duration, clinical course, and the level of neurologic disability. These hypointensities have been reported to occur in the thalamus, basal ganglia, and rolandic cortex. We assessed whether T2 hypointensity is associated with the severity of white matter plaques and atrophy of MS brains. In 114 MS patients, hypointensity of the thalamus, putamen, caudate, and sensorimotor cortex was ordinally rated against age- and gender-matched normal controls on 1.5-T MRI fast spin-echo axial T2WI. Regional and global T2 hyperintense and T1 hypointense parenchymal lesion loads were ordinally rated. Enlargement of subarachnoid and ventricular spaces (atrophy) was ordinally rated vs. age- and gender-matched normal controls. T2 hypointensity was highly, positively correlated with many other MRI variables. Regression modeling showed that T2 hypointensity was related to total atrophy, total T2 lesion load, third ventricular enlargement, parietal atrophy, and to a lesser extent, frontal T1 lesions and cerebellar T2 lesions, but not related to gadolinium enhancement. Ordinal ratings of T2 lesions and central atrophy showed high correlations with quantitative computerized assessments. We conclude that gray matter hypointensity on T2WI may reflect pathologic iron deposition and brain degeneration in MS. This T2 hypointensity is associated with brain atrophy and other MR markers of tissue damage. Further study is warranted to determine if T2 hypointensity is predictive of disease course in MS and is a useful surrogate outcome measure in therapeutic trials.

Parental consumption of contaminated sport fish from Lake Ontario and predicted fecundability

Wildlife studies suggest that consumption of contaminated fish from the Great Lakes may expose humans to polychlorinated biphenyls and persistent chlorinated pesticides. To assess whether time to pregnancy or fecundability is affected, we conducted a telephone survey in 1993 with female members of the New York State Angler Cohort Study who were considering pregnancy between 1991 and 1994 (N = 2,445). Among the 1,234 (50%) women who became pregnant, 895 (73%) had a known time to pregnancy. Upon enrollment into the cohort in 1991, both partners reported duration and frequency of Lake Ontario sport fish consumption. We estimated lifetime exposure to polychlorinated biphenyls from recent consumption and used a discrete-time analog of Cox proportional hazards analysis to estimate conditional fecundability ratios and 95% confidence intervals (CIs) for fish consumption among couples with complete exposure data who discontinued birth control to become pregnant (N = 575). Maternal consumption of fish for 3-6 years was associated with reduced fecundability (fecundability ratio = 0.75; 95% CI = 0.59-0.91), as was more than a monthly fish meal in 1991 (fecundability ratio = 0.73; 95% CI = 0.54-0.98). Our findings suggest that maternal but not paternal consumption of contaminated fish may reduce fecundability among couples attempting pregnancy.

Fatigue in multiple sclerosis and its relationship to depression and neurologic disability

We studied multiple sclerosis fatigue (MSF) and its relationship to depression and disability. Seventy-one patients [50 relapsing-remitting, 21 secondary progressive] were grouped by Fatigue Severity Scale (FSS) into MS-fatigue (MSF) (FSS>/=5; n=46) or MS-nonfatigue (MSNF) (FSS</=4; n=20). Forty-one patients were grouped into MS-depression (MSD) (n=15) or MS-nondepression (MSND) (n=26) by interview. Higher expanded disability status scale (EDSS) scores were noted in MSF than MSNF patients (P=0.0003); EDSS scores correlated with FSS scores (rho=0.43, P=0.003). However, fatigue was present in 58% (n=29) of relapsing-remitting patients and in 52% (n=26) of patients with mild physical disability (EDSS<3.5). Hamilton/Beck depression severity scores were higher in MSF than MSNF patients and correlated with FSS scores (P<0.05). MSD had higher FSS scores than MSND patients (P=0.008). After controlling for EDSS, depression severity continued to correlate with FSS scores (rho=0.37, P=0.02). After controlling for depression, FSS scores no longer correlated with EDSS scores (rho=0.27, P=0.09). Thus, MSF is independent of physical disability, but is associated with depression, suggesting that common mechanisms play a role in MSF and MSD including psychological factors or brain lesions in specific neuroanatomic pathways. Further study is warranted to determine if antidepressant medications improve fatigue in MS.

Double-stranded hamstring tendons for anterior cruciate ligament reconstruction

Bone-patellar tendon-bone autograft is the most commonly used tissue for ACL reconstruction; however, the harvesting of patellar tendon as a free graft can lead to significant morbidity. Alternate grafts may lower morbidity, yet the most commonly used alternate grafts including the double-stranded semi-tendinosus or gracilis have not been studied biomechanically. This study investigated the morphometric and biomechanical properties of double-stranded semi-tendinosus and gracilis tendons separately along with the patellar and quadriceps tendons obtained bilaterally from six fresh, 77-year-old cadaveric specimens. The quadriceps tendon was the thickest and therefore had the largest cross-sectional area, whereas double-stranded semitendinosus had the highest mean peak load to failure (1029+/-158.4 N), 11.5% and 10.3% stronger than patellar tendon and quadriceps tendons, respectively. Midsubstance rupture occurred in the hamstring tendons, whereas the patellar and quadriceps tendons failed at the bone-tendon junctions. Semitendinosus tendons with higher cross-sectional area had higher peak loads to failure. This linear relationship between cross-sectional area and the peak load to rupture also was observed in the other tendon groups (except gracilis). These results indicate that despite a lower cross-sectional area of the double-stranded semitendinosus, this tendon demonstrated a comparable mean peak load to rupture and stress compared with patellar and quadriceps tendons. It also was demonstrated that combined double-stranded semitendinosus and gracilis tendons produce a stronger graft with initial strength twice that of the patellar tendon, but requires further testing.

Influence of family history on clinical expression of Tourette's syndrome

OBJECTIVE

To determine the influence of family history on clinical expression of Tourette's syndrome (TS).

BACKGROUND

Recent studies have suggested that clinical expression of TS is similar among sporadic (SP) and familial patients but may be influenced by bilineal (BIL) transmission of tics or obsessive-compulsive behavior (OCB) in high-density pedigrees.

METHODS

The authors used family history methodology, supported by direct examination of affected relatives in 73% of familial patients, to determine the frequency of SP TS, and of unilineal (UNL) and BIL transmission of tics or OCB in 111 consecutively ascertained juvenile TS patients. For individuals in each group, severity of tics, attention deficit hyperactivity disorder (ADHD), and OCB were assessed at presentation and after a mean follow-up interval of 2.6 years, using the Tourette's Syndrome Global Scale and the Clinical Global Impression scales. The phenomenology of OCB was evaluated using the symptom checklist of the Children's Yale-Brown Obsessive Compulsive Scale.

RESULTS

The authors documented BIL transmission of tics in seven patients (6%). Patient age and sex were similar for the SP (n = 21; 19%), UNL (n = 66; 59%), and BIL (n = 24; 22%) groups, as was ADHD and tic severity at presentation and follow-up. Severity of OCB differed significantly between groups, with moderate to severe OCB affecting 5% of SP, 12% of UNL, and 37% of BIL patients at presentation (p = 0.007), and 5% of SP, 17% of UNL, and 54% of BIL patients at follow-up (p = 0.0001). Relative to UNL or SP patients, BIL patients were more likely to exhibit self-injurious behaviors (p = 0.0005).

CONCLUSIONS

OCB is less prominent in SP than in familial TS, perhaps reflecting a more restricted pathophysiology in this subgroup. Although BIL transmission of tics is relatively infrequent in consecutive TS pedigrees, cotransmission of OCB from an otherwise unaffected parent is common and significantly influences development of OCB and self-injurious behaviors, but not tics, in offspring. Genetic heterogeneity, epigenetic factors, and gene-environment interactions may play a more important role than genetic dosage effects in determining tic severity in TS.

Mechanism controlling sleep organization of the obese Zucker rats

We tested the hypothesis that the obese (fa/fa) Zucker rat has a sleep organization that differs from that of lean Zucker rats. We used the polygraphic technique to identify and to quantify the distribution of the three main states of the rat: wakefulness (W), non-rapid-eye-movement (NREM), and rapid-eye movement (REM) sleep states. Assessment of states was made with light present (1000-1600), at the rats thermoneutral temperature of 29 degrees C. Obese rats, compared with lean ones, did not show significant differences in the total time spent in the three main states. Whereas the mean durations of W and REM states did not differ statistically, that of NREM did (P = 0.046). However, in the obese rats, the frequencies of switching from NREM sleep to W, which increased, and from NREM to REM sleep, which decreased, were statistically significantly different (P = 0.019). Frequency of switching from either REM or W state was not significantly different. We conclude that sleep organization differs between lean and obese Zucker rats and that it is due to a disparity in switching from NREM sleep to either W or REM sleep and the mean duration of NREM sleep.

Cerebral surface pH changes during asphyxia, hypotension, and circulatory arrest in the dog

A technic is described for the measurement of cerebral surface pH in acute experiments in anesthetized dogs. During asphyxia and circulatory arrest, cerebral surface pH fell promptly and more profoundly than arterial blood or muscle surface pH; during hypovolemic hypotension (30 to 50 torr) cerebral surface pH declined later and less than muscle surface pH. The cerebral surface pH reflects the pH of the cortical interstitial fluid. Since the blood brain barrier is effectively impermeable to lactate, the changes recorded in the cerebral surface pH are a useful index of cortical intracellular metabolism.