The influence of being overweight on the relationship between shift work and increased total cholesterol level.

PURPOSE: The aim of this study was to clarify the influence of shift work on serum total cholesterol (T-Cho) levels according to body mass index (BMI) at entry in Japanese male workers. METHODS: A 14-year prospective cohort study was conducted in day workers (n = 4079) and alternating shift workers (n = 2807) who received annual health check-ups between 1991 and 2005 in a Japanese steel company. The association between job schedule and increases in T-Cho was investigated using multivariate pooled logistic regression analyses with age, BMI, lifestyle (smoking habit, drinking habit, habitual exercise), and the results of blood chemistries (creatinine, glycosylated hemoglobin A1c, aspartic aminotransferase, γ-glutamyl transpeptidase, uric acid) serving as covariates in those who were not overweight (BMI < 25 kg/m(2), n = 5082) and overweight (BMI ≥ 25 kg/m(2), n = 1804) at entry, respectively. The endpoints in the study were either a 20%, 25%, 30%, 35%, 40%, or 45% increase in T-Cho during the period of observation compared to T-Cho at entry. RESULTS: In subjects who were not overweight at entry, alternating shift work was associated significantly with five serum T-Cho endpoints (≥20%: odds ratio [OR] = 1.15, 95% confidence interval [CI)] = 1.05, 1.26; ≥25%: OR = 1.17, 95% CI = 1.05, 1.31; ≥35%: OR = 1.24, 95% CI = 1.05, 1.46; ≥40%: OR = 1.30, 95% CI = 1.06, 1.61; ≥45%: OR = 1.31, 95% CI = 1.01, 1.71). However, alternating shift work was not associated with any of the six T-Cho endpoints in subjects who were overweight at entry. CONCLUSIONS: In the present study, shift work was shown to be a potential risk factor for increased T-Cho in non-overweight Japanese male workers. However, we did not obtain a consistent association between shift work and an increase in T-Cho levels in overweight subjects. The results suggest that the effect of shift work on lipid regulation may be influenced by BMI.

Application of hybrid approach for estimating the benchmark dose of urinary cadmium for adverse renal effects in the general population of Japan.

We used an updated hybrid approach to estimate the benchmark doses and their 95% lower confidence limits (BMDL) for cadmium-induced renal effects in humans. Participants were 828 inhabitants (410 men, 418 women), aged 40-59 years who lived in three areas without any known environmental cadmium pollution. We measured urinary cadmium (U-Cd) as a marker of exposure, and urinary protein, ß2-microglobulin (ß2-MG) and N-acetyl-ß-D-glucosaminidase (NAG) as markers of renal effects. For urinary protein, the BMDL ranged from 0.9 to 1.1 µg g⁻¹ creatinine (cre) and approximately 1.6 µg per 24 h in men, and from 1.9 to 3.4 µg g⁻¹ cre and 2.0 µg per 24 h in women. For the renal tubular markers ß2-MG and NAG, the BMDL for U-Cd ranged from 0.6 to 1.2 µg g⁻¹ cre and from 0.8 to 1.7 µg per 24 h in men, and from 0.6 to 2.3 µg g⁻¹ cre and from 0.6 to 2.1 µg per 24 h in women. The lowest BMDL for urinary cadmium (0.6 µg g⁻¹ cre) was somewhat lower than average urinary cadmium in Japanese older population. These results suggest the importance of measures to decrease cadmium exposure in the general population of Japan.

Reassessment of the threshold of urinary cadmium by using hybrid approach in a cadmium non-polluted area in Japan.

BACKGROUND AND OBJECTIVES: We applied an updated hybrid approach to estimate the benchmark doses (BMD) and their 95% lower confidence limits (BMDL) for cadmium-induced renal effects as the threshold of urinary cadmium in humans. Using this method, the BMD and BMDL were estimated based on continuous exposure and continuous effect marker, thereby avoiding categorization of subjects, an inevitable outcome of previously used approaches. METHODS: The target subjects were 547 men and 723 women, aged 50 years or older, who lived in a cadmium non-polluted area of Japan. We measured urinary cadmium (U-Cd) as a marker of long-term exposure, and urinary protein, ß2-microglobulin (ß2-MG) and N-acetyl-ß-D-glucosaminidase (NAG) as renal effect markers. BMD and BMDL corresponding to an additional risk (BMR) of 5%, were calculated with the background risk at zero exposure set at 5%. RESULTS AND CONCLUSIONS: The BMDL of U-Cd for renal effect markers were 2.1 (urinary protein), 2.6 (ß2-MG) and 4.1 (NAG) µg/g creatinine in men and 1.5 (urinary protein), 1.4 (ß2-MG) and 3.1 (NAG) µg/g creatinine in women. The BMDLs in the present study may contribute to further discussion on health risk assessment of cadmium exposure, when compared to BMDLs obtained by previously reported methods.

Application of the hybrid approach to the benchmark dose of urinary cadmium as the reference level for renal effects in cadmium polluted and non-polluted areas in Japan.

OBJECTIVES: The aim of this study was to evaluate the reference level of urinary cadmium (Cd) that caused renal effects. An updated hybrid approach was used to estimate the benchmark doses (BMDs) and their 95% lower confidence limits (BMDL) in subjects with a wide range of exposure to Cd. METHODS: The total number of subjects was 1509 (650 men and 859 women) in non-polluted areas and 3103 (1397 men and 1706 women) in the environmentally exposed Kakehashi river basin. We measured urinary cadmium (U-Cd) as a marker of long-term exposure, and ß2-microglobulin (ß2-MG) as a marker of renal effects. The BMD and BMDL that corresponded to an additional risk (BMR) of 5% were calculated with background risk at zero exposure set at 5%. RESULTS: The U-Cd BMDL for ß2-MG was 3.5µg/g creatinine in men and 3.7 µg/g creatinine in women. CONCLUSIONS: The BMDL values for a wide range of U-Cd were generally within the range of values measured in non-polluted areas in Japan. This indicated that the hybrid approach is a robust method for different ranges of cadmium exposure. The present results may contribute further to recent discussions on health risk assessment of Cd exposure.

Estimation of the benchmark duration of shiftwork associated with weight gain in male Japanese workers.

The authors estimated the benchmark durations (BMDs) and their 95% lower confidence limit (BMDL) for the reference duration of shiftwork for weight gain. A 14-yr prospective cohort study was conducted in male workers at a Japanese steel company (n = 7254) who had received annual health check-ups between 1991 and 2005. The endpoints in the study were either a 5%, 7.5%, or 10% increase in body mass index (BMI) during the period of observation, compared to the BMI at entry. The association between the duration of shiftwork and weight gain was investigated using multivariate pooled logistic regression analyses with stepwise selection of covariates, including age, BMI measured during the study, drinking and smoking habits, and habitual exercise. The BMDL/BMD for shiftwork in subjects aged in their 40s or ≥50 yrs was estimated using benchmark responses (BMRs) of 5% or 10% and parameters for the duration of shiftwork and other covariates. For workers aged in their 40s, the BMDL/BMD for shiftwork with a BMR of 5% was 18.6/23.0 yrs (≥7.5%) and 16.9/19.4 yrs (≥10%). For workers aged ≥50 yrs, the BMDL/BMD with a BMR of 5% was 22.9/28.2 yrs (≥7.5%) and 20.6/23.6 yrs (≥10%). The reference duration of shiftwork that associated with weight gain was shown to be at least 17 yrs in middle-aged workers. Special attention should be paid to prevent weight gain at an earlier stage and not when this increase in weight has become apparent.

Calculation of the benchmark duration of shift work associated with the development of impaired glucose metabolism: a 14-year cohort study on 7104 male workers.

OBJECTIVES: The aim of this study was to calculate the benchmark doses (BMD) and their 95% lower confidence boundary (BMDL) for the threshold number of years of shift work associated with a relative increase in haemoglobin A1c (HbA(1c)), an index of glucose metabolism. METHODS: A 14-year prospective cohort study was conducted in male workers at a Japanese steel company (n=7104) who had received annual health check-ups between 1991 and 2005. The endpoints were either a 10%, 15%, 20%, 25% or 30% increase in HbA(1c) levels during the observation period, compared to HbA(1c) at entry to the study. The associations between years of shift work and increases in HbA(1c) were investigated using pooled logistic regression, adjusted for age, body mass index, mean arterial pressure, total serum cholesterol, creatinine, alanine aminotransferase, gamma-glutamyl transpeptidase, uric acid, drinking habits, smoking habits and habitual exercise. RESULTS: The BMDL/BMD for years of shift work were calculated using benchmark responses (BMRs) of 5% or 10% and parameters for duration of shift work and other covariates. Assuming a mean age of 53 years in workers aged 50 years or older, the BMDL/BMD for years of shift work with a BMR of 5% were 17.8/23.9 (> or = 15%), 15.7/18.7 (> or = 20%), 18.9/22.7 (> or = 25%) and 25.2/31.7 (> or = 30%). With a BMR of 10%, the respective values were 29.5/39.7 (> or = 15%), 24.3/28.9 (> or = 20%), 27.3/32.7 (> or = 25%) and 34.1/42.9 (> or = 30%). CONCLUSION: These results suggest that special attention should be paid to middle-aged workers whose years of shift work exceeds these threshold times.

Recent applications of benchmark dose method for estimation of reference cadmium exposure for renal effects in man.

The initial sign of cadmium (Cd)-induced renal effects is tubular damage, followed by glomerular damage. For the prevention of Cd-induced renal effects, it is essential to establish the reference exposure below which the risk of adverse health effects is low. In earlier Japanese studies, the estimated reference exposure of creatinine (cre)-adjusted urinary cadmium for renal tubular effect ranged from 1.6 to 4.0 microg/g cre in men and 2.3 to 4.6 microg/g cre in women. The benchmark dose (BMD) is defined as the exposure that corresponds to a certain response change from the background. The lower 95% confidence limit of the BMD (BMDL) can be used in risk assessment as a replacement for the no observed adverse effect level. This is a review of all relevant BMDL of Cd exposure for renal effects estimated so far. Based on studies in Japan, the best estimate is considered to be 1.5-3.2 microg/g cre for urinary Cd, 0.09-0.13 mg/kg for rice Cd concentration, and 0.9-1.4 g Cd for lifetime Cd intake. These BMDLs for renal effects were generally lower than the reference exposure expected from earlier studies, indicating the importance of further discussion regarding comprehensive measures to decrease the Cd exposure in the general population.

Estimation of the benchmark duration of alternating shift work associated with increased total cholesterol levels among male Japanese workers.

OBJECTIVE: The aim of this study was to estimate the benchmark doses (BMD) and their 95% lower confidence limits (BMDL) for the threshold number of years of alternating shift work associated with a relative increase in serum total cholesterol level (T-Cho), as an index of lipid metabolism. METHODS: We conducted a 14-year prospective cohort study among male workers (N=6886) at a Japanese steel company who had received annual health check-ups between 1991 and 2005. The endpoints were either a 20, 25, 30, 35, 40 or 45% increase in T-Cho levels during the observation period, compared to T-Cho at baseline. We investigated the associations between the years of alternating shift work and the relative increases in T-Cho using pooled logistic regression, adjusted for other potential covariates. RESULTS: We estimated the BMDL and BMD for years of alternating shift work among 40-, 50-, or >50-year old subjects using benchmark responses (BMR) of 5 or 10% and parameters for the duration of alternating shift work and other covariates. Assuming a mean age of 44 years among workers in their 40s, the BMDL/BMD for years of alternating shift work with a BMR of 5% were 21.0/28.0 (> or =20%), 21.3/26.1 (> or =25%), 24.1/28.8 (> or =30%), 25.6/29.8 (> or =35%), 27.1/31.5 (> or =40%), and 27.7/32.1 (> or =45%). CONCLUSIONS: The threshold number of years of alternating shift work that caused a 5% increase in T-Cho was shown to be > or =21 years among middle-aged workers. Special attention should be paid to influence the process at an earlier stage and not when the risk has already materialized.

Working hours and mental and physical fatigue in Japanese workers.

BACKGROUND: Establishing a threshold number of working hours is very important when making recommendations to protect people from the potentially harmful health effects caused by long working hours. AIM: To clarify the influence of working hours on both mental and physical symptoms of fatigue and use the data obtained to determine permissible working hours. METHODS: Cross-sectional survey of male day-shift workers using the Self-Rating Depression Scale (SDS) and the Cumulative Fatigue Symptoms Index (CFSI). Working hours were subdivided into six groups and odds ratios were calculated for positive outcomes on the SDS and CFSI using logistic regression analysis. RESULTS: A total of 715 workers participated. In the group working 260-279 h/month, the odds ratios for SDS and 'irritability', 'anxiety' and 'chronic tiredness' of the CFSI were significantly increased. In the group working >or=280 h/month, the odds ratios on CFSI for 'general fatigue', 'physical disorders', 'anxiety' and 'chronic tiredness' were likewise significantly increased. CONCLUSIONS: The present results clarified that working hours should be <260 h/month in order to minimize fatigue symptoms in male day workers.

Investigation of renal damage among residents in the cadmium-polluted Jinzu River basin, based on health examinations in 1967 and 1968.

The purpose of this study was to investigate the prevalence of renal disorders in the Jinzu River basin in Toyama Prefecture, Japan where Itai-itai disease was endemic, based on the results of epidemiological studies performed in 1967 and 1968. Furthermore, was there a regional accumulation of the prevalence of abnormal urinary findings in that area? Early morning urine samples were collected from 13 183 subjects (6155 men, 7028 women) who then responded to questionnaires about lifestyle and health. The subject participation rate was 90%. Our findings showed that subjects living in the area of the Jinzu River basin have significantly higher prevalence of abnormal urinary findings compared to subjects living in neighboring river basins and these geographical distributions demonstrated a definite regional accumulation in those areas. The findings of this study verified the regional accumulation of renal disorders in the Jinzu River basin and indicate an association of the occurrence of renal disorders with the water from the Jinzu River.

Estimation of the number of working hours critical for the development of mental and physical fatigue symptoms in Japanese male workers - application of benchmark dose method.

BACKGROUND: To clarify the influence of working hours on subjective fatigue symptoms and obtain the critical dose (number of hours) to determine the number of permissible working hours, we calculated the benchmark dose (BMD) and the 95% lower confidence limit on BMD (BMDL) of working hours for subjective mental and fatigue symptoms using multivariate logistic regression. METHODS: Self-administered questionnaires were distributed to all 843 male daytime workers aged < or = 60 years in a single chemical factory, and 715 provided complete replies. The odds ratios of daily working hours were determined using positive findings of the Self-rating Depression Scale and 8 subscales of the Cumulative Fatigue Symptom Index as dependent variables, and other potential covariates as independent variables. Using significant parameters for the working hours and those for other covariates, the BMD and BMDL (BMD/BMDL) values were calculated for corresponding dependent variables. The benchmark response (BMR) was set at 5% or 10%. RESULTS: The BMDL with a BMR of 5% was shown to be 9.6-11.6 hr per day, which corresponds to 48-58 working hours per week and 36-78 overtime hours per month. CONCLUSIONS: These results suggest that special attention should be paid to the workers whose working hours exceed these BMD/BMDL values.

Estimation of benchmark doses for urinary cadmium based on beta2-microglobulin excretion in cadmium-polluted regions of the Kakehashi River basin, Japan.

A benchmark dose low (BMDL) is used as a replacement for the no observed adverse effect level. The threshold levels of urinary cadmium (Cd) as BMDL were estimated using data from the Kakehashi River basin. The target population (>or=50 years) comprised 3178 and 294 participants inhabiting Cd-polluted and non-polluted areas, respectively. Cut-off values for beta2-MG-uria were defined as the 84 and 95% upper limit values calculated from control subjects, and 1000 microg/l or microg/g cr of beta2-MG. Using these cut-off values, the BMDL at which the excess risk is 0.05 was determined to be 2.9 - 4.0 microg/g cr (males) and 1.5 - 3.6 microg/g cr (females). The present study demonstrated that a BMD approach is useful to estimate the threshold level of urinary Cd in Cd-exposed subjects and people living in general environment without any known Cd-pollution since a BMD approach does not need abnormality rates of urinary findings in the controls.

Tissue cadmium (Cd) concentrations of people living in a Cd polluted area, Japan.

There are more than 50 cadmium (Cd) polluted areas in Japan. The severest general environmental Cd polluted area in Japan was the Jinzu River basin in Toyama Prefecture where Itai-itai disease had been endemic. The present study aimed to compare organ Cd concentrations of inhabitants who had been exposed to different levels of environmental Cd and to clarify the health effects of the environmental Cd exposure in Japan. Since 1960 we have measured tissue Cd concentrations of inhabitants with a history of living in a different Cd polluted areas. Study population living in Cd polluted areas were 36 (1 male, 35 females) patients with Itai-itai disease, 20 (7 males, 13 females) subjects suspected of having Itai-itai disease, 8 (2 males, 6 females) inhabitants in Cd polluted areas other than the Jinzu River basin. Subjects who had lived in Cd non-polluted area were 72 inhabitants. Cd concentrations in liver, pancreas and thyroid of those living in Cd polluted areas were as high as those of patients with Itai-itai disease, and their Cd concentrations in renal cortex were as low as those of patients with Itai-itai disease. The present study demonstrated that tissue Cd concentrations of some inhabitants in Cd polluted areas other than Jinzu River basin are equal to those of the patients with Itai-itai disease and that patients with Itai-itai disease were present even in these areas.

Cadmium exposure aggravates mortality more in women than in men.

This study aimed to examine whether the mortality associated with exposure to cadmium (Cd) differs between the sexes. Target subjects were 14,604 (6,944 men, 7,660 women) from a list of all residents in the Jinzu River basin in 1967 and 1968. Trend of proportion of the population aged 70 years and older was significantly higher in women in the following decreasing order: non-Jinzu River basin, a region receiving a mixed water supply, and the Jinzu River basin. Sex ratios (proportions of population of men to that of women) in those aged 70 years and older became significantly higher in the same order. This tendency was compatible with the geographical distribution of the prevalence of abnormal urinary findings and Cd concentration in rice which was grown and consumed in the area. This study revealed that Cd exposure aggravates mortality more in women than in men.

Smoking does not influence cadmium concentrations in blood and urine in relatively high levels of environmental cadmium areas in Japan.

We examined how the influence of smoking on blood and urinary cadmium (Cd) concentrations was modified by the level of environmental Cd. We measured blood and urinary Cd concentrations of 1134 men over 50 yr of age in three areas in Japan that were exposed to different levels of environmental Cd. Analysis of variance was used to compare Cd concentrations in blood and urine of smokers with those of nonsmokers living in the three areas. Correlation coefficients between the number of cigarettes smoked per day or smoking indices (the number of cigarettes smoked per day multiplied by the number of years smoked) and blood and urinary Cd concentrations were calculated. No significant difference in Cd concentrations between smokers and nonsmokers was observed in areas where the average Cd concentration in blood was over approx 2.4 ng/g, 2.0 mug/L in urine, and 2.3 mug/g creatinine in urine, respectively. Therefore, it was suggested that an influence of smoking on blood and urinary Cd concentrations was not observed in areas exposed to relatively high levels of environmental Cd.

Estimation of benchmark dose for renal dysfunction in a cadmium non-polluted area in Japan.

Previously, the association between urinary cadmium (Cd) concentration and indicators of renal dysfunction, including beta(2)-microglobulin (beta(2)-MG), total protein and N-acetyl-beta-D-glucosaminidase (NAG) were investigated in 1270 inhabitants > or = 50 years of age (547 men, 723 women) in a Cd non-polluted area in Japan and showed that a dose-response relationship existed between renal effects and Cd exposure in the general environment without any known Cd pollution. However, the threshold levels of urinary Cd could not be estimated at that time. In the present study, the threshold levels of urinary Cd were estimated as the benchmark dose low (BMDL) using the benchmark dose (BMD) approach. Urinary Cd excretion was divided into 6-7 categories, and an abnormality rate was calculated for each. Cut-off values for urinary substances were defined as corresponding to the 84% upper limit values, which were calculated from 2034 persons who had been living in the non-polluted areas and did not smoke. Then the BMD and BMDL were calculated using a log-logistic model. The values of BMD and BMDL for all urinary substances could be calculated. The BMDL for the 84% cut-off value of beta(2)-MG, setting an abnormal value at 5%, was 2.0 microg g(-1) creatinine (cr) in men and 1.6 microg g(-1) cr in women. In conclusion, the present study demonstrated that the threshold level of urinary Cd could be estimated in people living in the general environment without any known Cd-pollution in Japan, and the value was inferred to be almost the same as that in Belgium and Sweden.

Low-density lipoprotein receptor-related protein 5 variant Q89R is associated with hypertension in Japanese females.

We examined the influence of the Q89R variant in low-density lipoprotein receptor-related protein 5 on hypertension in a large Japanese cohort. We used multivariate logistic regression analysis to adjust for the effects of other factors known to influence hypertension such as age, body mass index, blood chemistry and lifestyle. Our cohort consisted of 1444 males and 1161 females selected from 3834 male and 2591 female workers in a single company. Hypertension was defined as systolic blood pressure 140 mmHg and/or diastolic blood pressure 90 mmHg or the use of antihypertensive medication. Because the RR genotype was so rare (three normotensive males and three normotensive females), they were excluded from analyses. Genotype distributions for Q89R in hypertensive females (QR = 14, QQ = 60) were significantly different (p = 0.033) from normotensive females (QR = 113, QQ = 971). In contrast, those in hypertensive males (QR = 26, QQ = 230) and in normotensive males (QR = 145, QQ = 1040) were similar. Allele distributions were not significantly different in either gender. In females, multivariate logistic regression showed that the QR genotype was associated with hypertension with odds ratio of 2.1 compared to the QQ genotype. This study indicates that the Q89R polymorphism is an independent factor for hypertension in Japanese females.

Health status of workers in small and medium-sized companies as compared to large companies in Japan.

The health status of workers in small companies has been noted to be relatively poor, but no actual comparisons of groups of variously sized companies within the same region based on the same methodology have ever been conducted. We undertook this study to clarify differences in health status according to company size. The subjects comprised workers of a Japanese steel company and various subcontractors who received health checkups in 2003. We obtained answers from 83 companies employing 11,844 workers and analyzed the data for 6,480 men aged 40 yr or more, comparing results of the health checkups, health management practices, and number of occupational health personnel according to company size (number of employees). Mean worker age in the various groups ranged from 49.7 to 54.0 yr. Drinking and smoking habits did not differ between them. There was a significant trend to higher prevalences of diabetes and hypertension, and lower prevalences of renal disease and hypercholesterolemia in smaller companies. Mean body mass index and diastolic blood pressure were significantly higher in companies with 1,000-2,999 workers. Health management practices satisfied the legal requirements of the respective company size. Occupational physicians devoted more time per worker in companies with 1,000-2,999 and 50-299 workers. No consistent differences were apparent between small and large companies in worker health status. Inter-company activities for occupational safety and health were undertaken and labor regulations almost equally adhered to. Endeavors to maintain a certain level of hygiene and health management play an important role in maintaining worker health in small companies.

A longitudinal study of the influence of smoking on the onset of obesity at a telecommunications company in Japan.

OBJECTIVE: To clarify the influence of smoking on the onset of obesity. METHODS.: A 5-year follow-up study was carried out on 25,312 workers at the time of their annual health check-up from 1992 to 1997. Pooled logistic regression analyses by sex were performed with age, working conditions and lifestyle as independent variables and the onset of obesity (BMI> or =26.4) as a dependent variable adjusted for the time period. RESULTS: In males, the following factors increased the risk of the onset of obesity: smoking equal to or more than 20 cigarettes per day (versus nonsmokers), monthly holidays fewer than 5 days (versus >7 days), one-way commute more than 90 min (versus< or =60 min), sleeping less than 5 h, moderate and high preference for fatty meals (versus little preference). In females, 30-39 years, 40-49 years and 50-59 years (versus 20-29 years), being an ex-smoker, smoking fewer than 20 cigarettes per day, smoking equal to or more than 20 cigarettes per day (versus nonsmokers, respectively) and high preference for fatty meals (versus little preference) increased the risk of the onset of obesity. CONCLUSION: This study revealed that smoking independently increases the risk of the onset of obesity regardless of sex.

Long-term longitudinal study on the relationship between alternating shift work and the onset of diabetes mellitus in male Japanese workers.

OBJECTIVE: This study investigated the effect of alternating shift work (ASW) on the onset of diabetes mellitus in Japanese workers compared with onset in day-shift work (DSW). METHODS: A longitudinal study was carried out on a DSW group (n = 3203) and ASW group (n = 2426) of a steel company who received their annual health checkups over a 10-year period between 1991 and 2001. The association between job schedule type and onset of diabetes mellitus (glycated hemoglobin A1c > or =6.0% or medication) was investigated by multivariate pooled logistic regression analyses. RESULTS: The odds ratio (95% confidence interval) for the development of diabetes mellitus in the ASW group compared with the DSW group was 1.35 (1.05-1.75). CONCLUSIONS: Our study revealed that the ASW is an independent risk factor for the onset of diabetes mellitus.