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Biomedical subjects

Akira Okayama

Publications and source records attributed to Akira Okayama.

At least 55 records · Page 3Linked to original sources
PubMed2005

Plasma B-type natriuretic peptide levels and risk factors for congestive heart failure in a Japanese general population.

This cross-sectional study was performed to establish the rationale for BNP testing for identifying subjects at high risk of congestive heart failure (CHF) in a screening setting. Plasma BNP concentrations were measured in 8,178 community-dwelling residents (mean age, 62 +/- 12 years; 3,194 males). First, in order to determine age- and sex-related reference values for plasma BNP levels, subjects having factors known to influence plasma BNP levels were excluded. The remaining 3,410 subjects were eligible for the reference study. Second, to verify BNP testing for screening for subjects at high risk of CHF, the clinical characteristics of subjects showing abnormally high plasma BNP levels (> or = 97.5 percentile for each age- and sex-specific value of the reference cohort) were examined. In the reference subjects, plasma BNP levels increased with age in both genders, and were higher in women than in men. In the original cohort, age- and sex-specific reference values for high plasma BNP levels were related to the presence of major ECG abnormalities, hypertension, mildly elevated serum creatinine levels, and a history of coronary heart disease. The results of the present study indicate that individuals with high plasma BNP levels in the community have accumulating risk factors for CHF. This suggests that plasma BNP measurement may be a useful screening test for identification of individuals at high risk of CHF within a Japanese general population.

Adult↗
PubMed2005

Comparison of positive cases for B-type natriuretic peptide and ECG testing for identification of precursor forms of heart failure in an elderly population.

Plasma B-type natriuretic peptide (BNP) levels have been reported to be elevated in various types of cardiac disorders and in precursors of CHF. To elucidate the potential ability of BNP testing to identify individuals with structural cardiac disease (ie, hypertensive heart disease, coronary heart disease, valvular heart disease) among community-dwelling elderly persons, cases which were positive on BNP testing were compared to those positive on ECG testing. In the initial phase, we performed plasma BNP measurements and ECG in 856 participants (age > or = 65 years) selected from a general population. From within this group, subjects with an abnormal ECG (n = 125) were selected according to the Minnesota code. Subjects with elevated BNP were selected independently on the basis of plasma levels (n = 112). In the next phase, subjects in both groups were invited to complete Rose's angina questionnaire and to undergo physical examination and transthoracic echocardiography. In this subject group (positive in ECG testing and/or BNP testing), the two tests had comparable sensitivity (65% versus 59%: NS) and specificity (40% versus 41%: NS) for identifying hypertensive heart disease (n = 17). For coronary heart disease (n = 12), the two tests had also comparable sensitivity (58% versus 42%: NS) and specificity (39% versus 41%: NS). However, for selection of valvular heart disease (n = 7), BNP testing had higher sensitivity than ECG testing (100% versus 14%; P < 0.01) with comparable specificity (43% versus 40%: NS). Several types of structural heart disease, in particular valvular heart disease, could be identified exclusively by BNP testing, suggesting that BNP measurement can make a significant contribution to screening for CHF precursors when used in combination with ECG in elderly populations.

Aged↗
PubMed2005

A cross-sectional study of alcohol drinking and health-related quality of life among male workers in Japan.

BACKGROUND: Although light and moderate alcohol drinkers are likely to have better subjective health, the sub-scales for subjective health have not been well documented. METHODS: We studied 4,521 male workers aged 25 yr and older with no history of cancer or cardiovascular disease, in 12 occupational groups in Japan. Data were from the High-risk and Population Strategy for Occupational Health Promotion Study (HIPOP-OHP). Drinking status was classified according to daily alcohol intake or frequency of drinking. We assessed the health-related quality of life (HRQOL) based on scores for five scales of the SF-36. RESULTS: Decreased odds ratios of sub-optimal HRQOL conditions, defined as less than the median SF-36 scores, for Role-Physical and General Health were found among persons who consumed 1.0 to 22.9 g/d of alcohol. Odds ratios for sub-optimal Vitality conditions were lowered according to increased levels of alcohol intake. Role-Emotional scores were not associated with alcohol drinking. People who drank 5 to 6 d/wk had higher levels of Role-Physical and Vitality, and those who drank 1 to 2 d/wk had better Vitality and Mental Health scores than non-drinkers. When adjusted for age, marital status, working hours, physical activity at work, self-reported job stress, smoking, regular exercise, hypertension, hyperlipidemia, and diabetes, the associations were almost unchanged except for General Health. CONCLUSIONS: Associations of drinking patterns with subjective health varied in five sub-scales of the SF-36. Overall, alcohol drinkers rated their health as good in comparison with non-drinkers.

Adult↗
PubMed2005

A nineteen-year cohort study on the relationship of electrocardiographic findings to all cause mortality among subjects in the national survey on circulatory disorders, NIPPON DATA80.

BACKGROUND: Electrocardiogram (ECG) is one of the most popular tools for daily clinics and health checkup, and has been used for the National Survey on Circulatory Disorders to assess the health status in Japanese people. The meaningfulness to predict mortality from all causes among people with ECG abnormality is to be clarified using national samples. METHODS: ECG findings recorded among 9,638 subjects for National Survey on Circulatory Disorders 1980 in Japan, were classified using the Minnesota Codes (mc). Their relationships to all cause mortality over 19 years were examined using Cox proportional hazard models adjusting for sex, age, systolic blood pressure, blood glucose, and smoking habits. RESULTS: Subjects with abnormal Q-QS findings showed significantly high hazard ratios ( 3.71(mc1-1) and 1.57 (mc1-3)) for mortality to the subjects who were free from any major ECG findings. Hazard ratios were 1.37 (mc2-1) to 4.16 (mc2-5) for axis deviation, and 1.34 (mc3-1) to 1.35 (mc3-3) for left high R waves. Those were 1.63 (mc4-3) to 2.59 (mc4-1) for ST depression, and 1.54 (mc5-3) to 2.33 (mc5-1) for T abnormality. The lower the second number of the Minnesota Codes was, the higher hazard ratio was observed in the Q-QS, ST, T codes. The hazard ratios of junction-type ST depression (mc4-4), and low T waves (mc5-4, 5-5) were not significant. CONCLUSIONS: ECG findings defined by the Minnesota Codes were useful to predict the risk for mortality from all causes even after adjusting for the other major risk factors, and the results supported a usefulness of the ECG for health check-ups.

Adult↗
PubMed2005

Proteinuria is a prognostic marker for cardiovascular mortality: NIPPON DATA 80, 1980-1999.

BACKGROUND: Proteinuria has been considered to be a prognostic marker for persons with diabetes mellitus, but only a limited number of studies about the relationship between proteinuria and mortality among general population has been available. METHODS: The subjects were 10,897 individuals who participated in the National Cardiovascular Survey conducted in 1980 and who were aged 30 years or older living in 300 districts that had been randomly selected throughout Japan. The vital records were confirmed in 1999 and 7,203 subjects (3,180 males and 4,023 females) without a history of hypertension, stroke, heart disease, renal disease, or diabetes mellitus at the start of the study were investigated. RESULTS: There were 126,825 person-years of follow-up. During the observed period of time, 371 died of cardiovascular causes, including 171 stroke deaths and 74 coronary deaths. The risk of proteinuria for cardiovascular mortality was greater than unity for those with a normal serum creatinine level, after adjusting for age and other cardiovascular disease risk factors. CONCLUSIONS: When contrasted with other cardiovascular disease risk factors, urinary protein is an independent risk factor for cardiovascular death among the Japanese population.

Adult↗
PubMed2005

Knowledge of and attitudes toward suicide and depression among Japanese in municipalities with high suicide rates.

BACKGROUND: Knowledge of and attitudes toward suicide and depression have not been fully investigated in Japan. METHODS: Study areas comprised municipalities in northern Japan where standardized mortality ratios (SMRs) from suicide compared with a Japanese standard ranged from 1.62 to 3.72 in men and from 1.43 to 3.49 in women. We conducted a questionnaire survey on a random sample of 7,136 participants aged 20 to 79 years, and analyzed data of 5,547 (77.7%) subjects. We categorized seven municipalities, from which the subjects were drawn, into three groups according to the SMR from suicide. Self-Rating Depression Scale (SDS) score was used for evaluation of depressive states. RESULTS: The SDS score was significantly higher in the high SMR group in women, but no significant difference among the three SMR groups was observed in men. The percentage of subjects with nine years or less of education was significantly higher in the high SMR group both in men and in women. The percentage of men who drank alcohol once a week or more was significantly higher in the high SMR group. The percentages of subjects unaware that depressive states are treatable by medication were not significantly different among the three SMR groups both in men and in women, while the percentage of men unwilling to see a psychiatrist when depressed was the lowest in the high SMR group. CONCLUSION: Although a significant difference in SDS score was observed in women, most of the psychosocial factors or knowledge of and attitudes toward suicide and depression were not adversely associated with SMR group.

Adult↗
PubMed2005

Cardiovascular risk factors in hemodialysis patients: results from baseline data of kaleidoscopic approaches to patients with end-stage renal disease study.

BACKGROUND: The prevalence of cardiovascular risk factors and the prevalence of comorbidities in adult hemodialysis patients in Japan are not fully understood. METHODS: In "Kaleidoscopic Approaches to Patients with End-stage Renal Disease Study" (The KAREN Study, 2003), trained research stuff examined 1,214 adult hemodialysis patients (mean age, 61.2 years; 779 males and 435 females) of 1,506 patients in northern areas of Iwate Prefecture. Cardiovascular risk factors and the prevalence of comorbidities in hemodialysis patients were compared with those in the general population using direct age-adjustment methodology and standardized morbidity ratios (SMRs). RESULTS: In hemodialysis patients, common causes of end-stage renal disease were chronic glomerulonephritis (29.8%), diabetic nephropathy (24.5%), and other diseases. Prevalence and SMR of myocardial infarction were 5% and 9.6, respectively, and those of stroke were 13% and 5.7. The prevalences of hypertension and diabetes mellitus were 87% and 29%, respectively. Mean systolic blood pressure and mean diastolic blood pressure were 155 mmHg and 85 mmHg, respectively. Mean levels of total serum cholesterol, high-density lipoprotein cholesterol, and albumin in patients with end-stage renal disease were lower than those of the general population (160.6 vs. 203.3 mg/dL, 48.5 vs. 59.7 mg/dL, and 3.7 vs. 4.4 g/dL, respectively). Mean levels of C-reactive protein were higher than those of the general population (3.80 vs. 1.16 mg/L). CONCLUSION: Hemodialysis patients have a high prevalence of cardiovascular risk factors and comorbidities. Levels of nutrition-related markers were lower, and C-reactive protein levels were higher, in hemodialysis patients than in the general population.

Adult↗
PubMed2005

Health effects of cadmium exposure in the general environment in Japan with special reference to the lower limit of the benchmark dose as the threshold level of urinary cadmium.

OBJECTIVES: This study investigates renal dysfunction in areas without known environmental cadmium pollution and calculates the threshold level of urinary cadmium. METHODS: Urinary total protein, beta2-microglobulin (beta2-MG), and N-acetyl-beta-D-glucosaminidase (NAG), used as indicators of renal dysfunction, and urinary cadmium concentration, used as an indicator of cadmium exposure, were measured in two sets of 24-hour urine samples from each of 828 participants (410 men, 418 women), aged 40-59 years and living in three areas without any known environmental cadmium pollution. In multiple regression and logistic regression analyses the association between indicators of cadmium exposure and indicators of renal dysfunction were studied. The lower 95% confidence limit of the dose (benchmark dose) corresponding to a 5% (BMDL5) or 10% (BMDL10) level of each indicator of renal dysfunction above the background level) was calculated as the threshold level of urinary cadmium. RESULTS: With all the expressed units [g creatinine(-1) and day(-1)] in the multiple regression analysis, the partial regression coefficients showed a significant association between urinary cadmium concentration and total protein, beta2-MG, and NAG for both genders, except for total protein for women (g creatinine(-1) and day(-1). The same results were obtained for both genders in the logistic regression analysis. The BMDL10 was 0.6-1.2 microg/g creatinine and 0.8-1.6 microg/day for the men and 1.2-3.6 microg/g creatinine, and 0.5-4.7 microg/day for the women. CONCLUSIONS: Cadmium exposure and the levels of the indicators of renal dysfunction were associated among the men and women aged 40-59 years in areas without any known environmental cadmium pollution. The threshold level of urinary cadmium in Japan seems to be almost the same as in Belgium and Sweden.

Acetylglucosaminidase↗
PubMed2005

Knowledge of smoking-related risks and opinions on tobacco control by smoking status and education level in Japan.

OBJECTIVE: We aimed to examine knowledge of smoking-related risks and opinions on tobacco control by smoking status and education level in Japan. METHODS: We conducted a questionnaire survey in 2002 on a random sample of residents aged 20 to 79 years in two neighboring districts of northern Japan. In a total sample of 7,136, we analyzed data from 5,638 (79.0%) subjects (2,659 men and 2,979 women). RESULTS: The length of education was positively associated with knowledge of smoking-related risks. Compared to current smokers, past male smokers and never female smokers were more likely to know about the harm of passive smoking. As for causal links between smoking and lung cancer, stroke, and low birth weight, those who had been educated longer tended to be more aware of the associations in both sexes. Compared to current smokers, past and never smokers of men and past smokers of women were more likely to know that smoking contributes to low birth weight, but no difference was observed between current and never female smokers in this regard. Opinions on tobacco control were associated with both smoking status and education level; past and never smokers compared to current smokers and those who were educated longer tended to be affirmative about tobacco control. CONCLUSION: Knowledge of smoking is largely associated with education, but opinions on tobacco control are dependent on both smoking status and education.

Adult↗
PubMed2004

Cigarette smoking as a risk factor for stroke death in Japan: NIPPON DATA80.

BACKGROUND AND PURPOSE: Some previous Japanese cohort studies failed to show an association between smoking and stroke risk. Because such an association has been noted in other populations, this issue should be re-examined in a recent representative Japanese cohort with a higher total cholesterol level. METHODS: A total of 9638 men and women aged 30 years and older without a history of cardiovascular disease (CVD) at baseline in 1980 were followed-up for 14 years. RESULTS: We observed 203 stroke deaths (107 cerebral infarctions, 45 cerebral hemorrhages, and 51 others), 191 heart disease deaths, and 413 CVD deaths. The average serum total cholesterol level was approximately 4.91 mmol/L. Cox proportional hazard ratios were calculated adjusting for age, systolic blood pressure, and other conventional risk factors. The hazard ratios for men who smoked 1 to 20 cigarettes/day for all strokes, cerebral infarction, and cerebral hemorrhage were 1.60 (95% CI, 0.91 to 2.79), 2.97 (CI, 1.27 to 6.98), and 0.42 (CI, 0.16 to 1.09), respectively, and for those who smoked > or =21 cigarettes/day, they were 2.17 (CI, 1.09 to 4.30), 3.26 (CI, 1.11 to 9.56), and 0.68 (CI, 0.20 to 2.33), respectively. For women who smoked > or =21 cigarettes/day, the hazard ratio for all strokes was 3.91 (CI, 1.18 to 12.90). For CVD, all heart disease, and ischemic heart disease, the hazard risks of smoking were significant (1.49 to 4.25) for men but not significant for women. CONCLUSIONS: Smoking in a cohort with moderate serum total cholesterol level was a potent risk factor for stroke, especially cerebral infarction, for both men and women, and for CVD and ischemic heart disease for men.

Adult↗
PubMed2004

Resting heart rate and cause-specific death in a 16.5-year cohort study of the Japanese general population.

BACKGROUND: Several prospective studies have reported resting heart rate (HR) to be a risk factor for certain cause-specific death, together with sex- or age-specific differences in the effects of HR on death. However, there have been few prospective data from non-Western populations. METHODS: Cohort study, over 16.5 years to date of death or end of follow-up (November 15, 1998) involving 8800 men and women > or =30 years of age randomly selected throughout Japan, who participated in the National Survey on Circulatory Disorders in 1980. Resting HR was determined from 3 consecutive intervals between R waves on the 12-lead electrocardiogram. RESULTS: For middle-aged men (30 to 59 years of age), in the highest quartile of HR, there was a significant positive association with cardiovascular (RR, 2.55; 95% CI, 1.22 to 5.31) and all-cause death (RR, 1.45; 95% CI, 1.06 to 2.00). For middle-aged women, in the highest quartile, there was a significant positive association with noncancer, noncardiovascular (RR, 2.41; 95% CI, 1.04 to 5.59), and all-cause death (RR, 1.94; 95% CI, 1.26 to 3.01). Resting HR also showed a significant positive association with cardiac events but not to stroke. These relations were not evident for elderly subjects (> or =60 years of age). Results were not affected when deaths within the first 5 years of follow-up were excluded, except for noncancer, noncardiovascular death. CONCLUSIONS: High resting HR is an independent predictor of long-term death in the Japanese general population.

Adult↗
PubMed2004

A combination of serum low albumin and above-average cholesterol level was associated with excess mortality.

BACKGROUND: There is no population-based prospective study concerning the relation between serum albumin and mortality in a non-Western population, and few previous studies included the subgroup analysis stratified by serum cholesterol level. METHODS: A 13.7-year cohort study was conducted on 6,957 males and females aged 30-59 years from 300 randomly selected areas throughout Japan, who participated in the National Survey on Circulatory Disorders in 1980. RESULTS: In the group with median and above of total cholesterol, one standard deviation (SD) increment of serum albumin (2.6 g/L for males and 2.4 g/L for females) was inversely associated with all-cause mortality for both males and females (relative risk RR = 0.68 and 0.81: 95% confidence interval CI = 0.53-0.87 and 0.68-0.98), and with cancer mortality for females (RR = 0.74; 95% Cl = 0.57-0.96);and the lowest category of serum albumin (< or = 43 g/L) showed the highest cardiovascular mortality for males (RR = 5.04; 95% CI = 1.04-24.5) among the three albumin categories. These relationships were not evident in the group with total cholesterol level below median. CONCLUSION: A combination of a low albumin level and above average cholesterol level, even both within the clinical normal range,is associated with excess mortality in the Japanese general population.

Adult↗
PubMed2004

Multigenerational family structure in Japanese society: impacts on stress and health behaviors among women and men.

Rapid population aging in Japan has led to rising demands for informal care giving. Traditionally, care giving for aging parents has fallen disproportionately on the shoulders of women living in multigenerational households. However, rising labor force participation by Japanese women, declining marriage and fertility rates, and women's changing expectations have combined to produce unprecedented strains on traditional multigenerational households where care giving to elders traditionally takes place. In this paper, we explored gender-specific relationships between family structure, stress and worries, and health behaviors, using linked data from two national surveys conducted in Japan: the 1995 Comprehensive Survey of the Living Conditions of People on Health and Welfare, and the 1995 National Nutrition Survey. We found that women in multigenerational households reported more care-giving worries, and also less future health and financial worries. Living with parents was associated with protective health behaviors (less smoking, less heavy drinking), but also more sedentary behavior among women, while men in "sandwich" families (i.e., living with both parents and children) reported heavier smoking. The association of family structure and health behavior was not mediated by worries. Living alone was associated with worse health for women. These findings suggest gender-specific patterns of worries and health behaviors that reflect both the health-protecting and health-damaging effects of living in multigenerational households.

Adult↗
PubMed2004

Egg consumption, serum cholesterol, and cause-specific and all-cause mortality: the National Integrated Project for Prospective Observation of Non-communicable Disease and Its Trends in the Aged, 1980 (NIPPON DATA80).

BACKGROUND: Because egg yolk has a high cholesterol concentration, limited egg consumption is often suggested to help prevent ischemic heart disease (IHD). OBJECTIVE: We epidemiologically examined the validity of this recommendation. DESIGN: We analyzed the relations of egg consumption to serum cholesterol and cause-specific and all-cause mortality by using the NIPPON DATA80 (National Integrated Project for Prospective Observation of Non-communicable Disease And its Trends in the Aged, 1980) database. At the baseline examination in 1980, a nutritional survey was performed by using the food-frequency method in Japanese subjects aged > or =30 y. We followed 5186 women and 4077 men for 14 y. RESULTS: The subjects were categorized into 5 egg consumption groups on the basis of their responses to a questionnaire (> or =2/d, 1/d, 1/2 d, 1-2/wk, and seldom). There were 69, 1396, 1667, 1742, and 315 women in each of the 5 groups, respectively. Age-adjusted total cholesterol (5.21, 5.04, 4.95, 4.91, and 4.92 mmol/L in the 5 egg consumption categories, respectively) was related to egg consumption (P < 0.0001, analysis of covariance). In women, unadjusted IHD mortality and all-cause mortality differed significantly between the groups [IHD mortality: 1.1, 0.5, 0.4, 0.5, and 2.0 per 1000 person-years, respectively (P = 0.008, chi-square test); all-cause mortality: 14.8, 8.0, 7.5, 7.5, and 14.5 per 1000 person-years, respectively (P < 0.0001, chi-square test)]. In men, egg consumption was not related to age-adjusted total cholesterol. Cox analysis found that, in women, all-cause mortality in the 1-2-eggs/wk group was significantly lower than that in the 1-egg/d group, whereas no such relations were noted in men. CONCLUSION: Limiting egg consumption may have some health benefits, at least in women in geographic areas where egg consumption makes a relatively large contribution to total dietary cholesterol intake.

Adult↗
PubMed2004

Factor analysis of Zung Scale scores in a Japanese general population.

The purpose of the present paper was to investigate the distribution of Zung Self-rating Depression Scale (SDS) scores in a general population and its factor structure. Questionnaires on SDS items were sent to 7136 randomly selected residents aged 20-79 years who lived in districts in Japan with high rates of suicide. Valid responses were received from 5547 residents (response rate: 77.7%). Factor analysis of the SDS scores was conducted. The SDS scores of the male subjects were significantly lower than those of the female subjects in all age groups. A reverse-J-shaped relationship was found between age groups and mean SDS scores for the male and female subjects. The highest mean score was in the age group of 20-39 years, and the lowest mean score was in the age group of 60-69 years for the male and female subjects. In factor analysis, two factors consisting of 12 items were extracted, and 10 of those 12 items covered six Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM-IV) criteria describing psychological disturbances of depression. The distribution of SDS scores differed depending on the age group. Major components of SDS in the subjects covered the DSM-IV criteria for psychological disturbances of depression.

Adult↗
PubMed2004

Association between serum C-reactive protein levels and microalbuminuria: a population-based cross-sectional study in northern Iwate, Japan.

OBJECTIVE: The presence of microalbuminuria is a renal marker of vascular endothelial damage, and is an independent and strong predictor of increased risk for cardiovascular mortality and morbidity. Elevated circulating C-reactive protein (CRP) levels have recently been reported to be a novel cardiovascular risk factor, and it has been suggested that this acute-phase protein impairs vascular endothelial function. The aim of the present study was to determine whether serum CRP level is a dependent or an independent risk factor of microalbuminuria in the general population. METHODS: Subjects of this cross-sectional study were apparently healthy individuals drawn from the general Japanese population (mean age, 62; men, 2,236; women, 4,217). Serum CRP levels were determined using a highly sensitive kit and urine albumin-creatinine ratio (UACR) was calculated using a single urine sample. Multivariate logistic regression analysis was used to determine which risk factors (ie, age, hypertension, diabetes, obesity, hypercholesterolemia, smoking, and CRP) might predict the presence of microalbuminuria. RESULTS: In addition to classical cardiovascular risk factors such as age, hypertension, diabetes and obesity, serum CRP levels are also significantly correlated with microalbuminuria in men (odds ratio = 1.42, 95% CI = 1.13-1.79; p < 0.01) and women (odds ratio = 1.25, 95% CI = 1.05-1.49; p < 0.01). When subjects with diabetes were excluded from the analysis, serum CRP levels continued to be a significant predictor for microalbuminuria (odds ratio = 1.35, 95% CI = 1.06-1.73; p < 0.05 for men: odds ratio = 1.23, 95% CI = 1.03-1.47; p < 0.05 for women). CONCLUSIONS: The present study has shown that low-grade inflammation as represented by high sensitivity CRP levels may be significantly related to the presence of microalbuminuria. This suggests that microalbuminuria may be a useful marker representing systemic low-grade inflammation as well as being an established cardiovascular risk factor in apparently healthy individuals.

Aged↗
PubMed2004

Assessment of smoking status among workers using an improved colorimetric method.

To monitor smoking status among workers, we improved the colorimetric method to detect cotinine and other nicotine metabolites in urine. In adding ethanol in the reaction mixture, the quantitative measurable time defined as the duration with more than 95% of the peak absorbance, extended to 80 min in contrast to 16 min in the original method. As the analytical condition, a aliquot of urine sample (0.5 ml) was mixed with 0.5 ml of ethanol, with 0.2 ml of 4 M acetate buffer (pH: 4.7), with 0.1 ml of 150 mM KCN, with 0.1 ml of 0.44 M chloramin and then with 0.5 ml of 78 mM barbituric acid. A linear relationship was observed between cotinine concentration up to 80 microM and absorbance at 508 nm (r=0.998, p<0.01). Mean levels of nicotine metabolites among non smokers and smokers were 4.9 and 47.4 microM cotinine equivalent, respectively. Sensitivity and specificity were 96.1% and 96.7%, respectively for nicotine metabolites concentration among workers (n=385) when adopting 6.9 microM cotinine equivalent as a cut off value and the area under the ROC curve was 0.982. This method can be applicable to quantitative detection of smoking status.

Colorimetry↗