Association of adulthood weight gain with circulating adipokine and insulin resistance in the Japanese population.

BACKGROUND/OBJECTIVES: Although adipokines and insulin resistance are known to be correlated with body fatness, it is unclear whether they are independently related to weight gain experience. We examined the associations of serum adipokines and marker of insulin resistance with past weight gain during adulthood by taking the degree of attained body mass index (BMI) level into consideration. SUBJECTS/METHODS: Subjects were 399 Japanese municipal employees, aged ⩾ 30 years, who participated in a health survey. Serum adipokines were measured using a Luminex suspension bead-based multiplexed array. Weight change during adulthood was calculated as the difference between measured current weight and recalled weight at the age of 20 years. Multiple regression was performed to calculate mean adipokine levels and homeostasis model assessment of insulin resistance (HOMA-IR) according to weight gain (< 5 kg, 5-9.9 kg, or ⩾ 10 kg) with adjustment for current BMI. RESULTS: Weight gain from the age of 20 years was significantly and positively associated with leptin levels even after adjustment for current BMI (P for trend < 0.001), whereas it was significantly and inversely associated with adiponectin levels in a BMI-adjusted model among subjects aged ⩾ 40 years (P for trend=0.03). Weight gain was associated with HOMA-IR in a BMI-unadjusted model (P for trend < 0.001), but this association was largely attenuated after adjustment for BMI. Resistin, plasminogen activator inhibitor-1 and visfatin were not associated with past weight gain. CONCLUSIONS: Results suggest that a large weight gain during adulthood is associated with higher leptin and lower adiponectin levels independently of the degree of attained BMI level.

Serum pyridoxal concentrations and depressive symptoms among Japanese adults: results from a prospective study.

BACKGROUND/OBJECTIVES: Vitamin B6 is suggested to have a protective role against depression. However, the association between vitamin B6 intake and depression remains inconclusive, and few studies have examined the relationship between circulating vitamin B6 concentrations and depressive symptoms. Here, we investigated the cross-sectional and prospective associations between serum pyridoxal concentrations and depressive symptoms among Japanese workers. SUBJECTS/METHODS: Participants were 422 municipal employees (aged 21-67 years) who participated in a baseline survey in 2006 for cross-sectional analysis, and 210 subjects without depressive symptoms at baseline (2006) who completed both baseline and follow-up (2009) surveys for prospective analysis. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Logistic regression analysis was used to estimate the odds ratio of depressive symptoms (CES-D scale of ≥ 19) according to tertile of serum pyridoxal with adjustment for potential confounding variables. RESULTS: In the cross-sectional analysis, serum pyridoxal concentrations were significantly associated with a decreased prevalence of depressive symptoms (P for trend=0.03); the multivariable-adjusted odds ratio of depressive symptoms for the highest tertile of pyridoxal was 0.54 (95% confidence interval 0.30-0.96) compared with the lowest tertile. In longitudinal analyses, higher serum pyridoxal concentrations at baseline were associated with a trend toward reduced depressive symptoms after 3 years; the multivariable-adjusted odds ratio of depressive symptoms for the highest versus the lowest tertile of pyridoxal concentration was 0.55 (95% confidence interval 0.13-2.32). CONCLUSIONS: A higher vitamin B6 status may be associated with a decreased risk of depressive symptoms in Japanese.

Serum 25-hydroxyvitamin D and markers of insulin resistance in a Japanese working population.

BACKGROUND/OBJECTIVES: The association between vitamin D status and insulin resistance (IR) has been less studied among Asians, and it remains elusive whether calcium could modify such an association. We examined the association of serum 25-hydroxyvitamin D (25(OH)D) concentrations with IR markers and the potential effect modification by calcium intake among a Japanese population. SUBJECTS/METHODS: The authors analyzed data (n=494) from a cross-sectional survey conducted in 2009 among a Japanese working population aged 20-68 years. Fasting serum 25(OH)D and insulin, as well as fasting plasma glucose were determined, and homeostatic model assessment of IR (HOMA-IR) was calculated. Calcium intake was assessed using a validated diet history questionnaire. Multiple linear regression was done with adjustment of potential confounding variables. RESULTS: Fasting insulin and HOMA-IR were significantly inversely associated with 25(OH)D concentration across quartiles of 25(OH)D after fully adjusting for covariates (P(trend)=0.04 and 0.02, respectively). Across clinically relevant categories of 25(OH)D, compared with participants in the vitamin D sufficiency group, those in the vitamin D insufficiency group had a 5% higher HOMA-IR score, and those in the hypovitaminosis D group had an 18% higher HOMA-IR score (P(trend)=0.01). In an analysis by calcium intake, the HOMA-IR score was highest among participants with both a low calcium intake and lowest 25(OH)D concentrations, with significant inverse trend being observed in the group with lower calcium intake (P(trend)=0.02). CONCLUSIONS: Our findings suggest that low vitamin D status is associated with IR among Japanese adults.

Misreporting of dietary energy, protein, potassium and sodium in relation to body mass index in young Japanese women.

OBJECTIVE: Although under-reporting of dietary intake is more common in persons with a high body mass index (BMI), it is not well known whether or not misreporting is selective for different foods (and hence energy and nutrients), particularly in non-Western populations. We examined misreporting of dietary intake against biomarkers and its relation with BMI in young Japanese women. DESIGN: Cross-sectional study. SUBJECTS: A total of 353 female Japanese dietetic students aged 18-22 years (mean BMI: 21.4 kg/m(2), mean fat intake: 29.8% of energy). METHODS: Misreporting of dietary energy, protein, potassium and sodium (assessed by a self-administered diet history questionnaire) was examined against respective biomarkers (estimated energy expenditure and 24-h urinary excretion). Reporting accuracy was calculated as the ratio of reported intake to that estimated from corresponding biomarkers (complete accuracy: 1.00). RESULTS: Mean reporting accuracy of absolute intake (amount per day) varied considerably (0.86-1.14). Reporting accuracy of absolute intake decreased with increasing BMI (P for trend <0.001). However, no association was observed between reporting accuracy of energy-adjusted values and BMI (P for trend >0.15), indicating that BMI-dependent misreporting was canceled by energy adjustment. This was owing to positive correlation between the reporting accuracy of energy intake and that of absolute intake of the three nutrients (Pearson correlation coefficient: 0.49-0.67, P<0.0001). CONCLUSIONS: Although differential misreporting of absolute intake was associated with BMI, differential misreporting of energy-adjusted value was not. These findings support the use of energy-adjusted values in the investigation of diet-disease relationships among lean populations with a low-fat intake.

Sex ratio in offspring of those affected by dioxin and dioxin-like compounds: the Yusho, Seveso, and Yucheng incidents.

Sex ratios in the offspring of those affected by dioxins or dioxin-like compounds have been reported from Seveso, Italy and Yucheng, Taiwan. The sex ratio of live births in Yusho, Japan after a similar accidental massive exposure to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) in 1968 are reviewed. Data on all births among parents exposed to the compounds from 1968 to 1977 in Fukuoka and a region of Nagasaki, the two areas affected, are reported. In total there were 85 live births in those regions. The sex ratio was not significantly different from normal (0.513). To evaluate hormonal disrupting activity or effects on reproductive outcome by PCBs and PCDFs, a further investigation of sex in offspring of the Yusho victims, especially offspring of those who were younger than 19 years of age at the time of the Yusho incident, is needed.

Apolipoprotein E genotype, serum lipids, and colorectal adenomas in Japanese men.

We examined the relation of serum lipids and apolipoprotein E genotype to colorectal adenomas among 205 cases and 220 controls with normal colonoscopy in Japanese men. With adjustment for body mass index, cigarette smoking, alcohol use, and other covaiates, odds ratios of proximal and distal adenomas associated with the presence of an allele varepsilon4 were 0.59 (95% confidence interval 0.23-1.45) and 0.99 (0.50-1.98), respectively. While serum total and LDL cholesterol were unrelated to both proximal and distal adenomas, serum triglycerides were positively related to distal adenomas. The findings suggest that altered lipid metabolism may be differentially associated with tumorigenesis in the proximal and distal colorectum.

Glutathione S-transferase polymorphisms and risk of colorectal adenomas.

Glutathione S-transferases (GSTs) are a superfamily of detoxification enzymes that may play an important role in human carcinogenesis. While the genetic polymorphisms GSTM1 and GSTT1 have drawn particular interest in relation to cancer susceptibility, previous studies of colorectal cancer are inconsistent regarding their role. We examined the relation between GSTM1 and GSTT1 genotypes combined and colorectal adenomas, and the interaction with cigarette smoking among 205 cases of colorectal adenomas and 220 controls with normal total colonoscopy in Japanese men. Neither GSTM1 nor GSTT1 was related to colorectal adenomas, nor were the null genotypes of GSTM1 and GSTT1 combined. The lack of an association with GSTM1 and GSTT1 genotypes combined persisted even when the analysis was done separately for proximal and distal colorectal adenomas. A three- to fivefold significant increase in the odds of colorectal adenomas was observed among men with a high exposure to cigarette smoking across the genotype groups, and a statistically significant increasing trend was noted within each genotype group. The present findings do not support the role for GSTM1 and GSTT1 genotypes in the development of colorectal adenomas.

Cigarette smoking, CYP1A1 MspI and GSTM1 genotypes, and colorectal adenomas.

Cigarette smoking has been related to increased risk of colorectal adenomas, but the underlying mechanisms are unknown. Genetic polymorphisms are known for enzymes involved in the activation of polycyclic aromatic hydrocarbons and other tobacco-related carcinogens. Polycyclic aromatic hydrocarbons are activated by cytochrome P4501A1 (CYP1A1) and detoxified by glutathione S-transferases. We investigated the relation of CYP1A1 MspI and GSTM1 genotypes to the risk of colorectal adenomas with special reference to interaction with cigarette smoking among 205 cases of colorectal adenomas and 220 controls with normal total colonoscopy in a male Japanese population. Cigarette smoking was strongly associated with increased risk of colorectal adenomas. Overall, neither the CYP1A1 MspI genotype nor the GSTM1 genotype was related to colorectal adenomas. A significant trend for increased risk of colorectal adenomas associated with smoking was observed for each of the CYP1A1 MspI genotypes, and the increasing trends did not differ by MspI genotype. The positive association between smoking and colorectal adenomas did not vary much with GSTM1 genotypes. Among former and current smokers, adenoma risk did not differ according to the combination of CYP1A1 MspI and GSTM1 genotypes. CYP1A1 MspI and GSTM1 genotypes do not seem to modify the risk of colorectal adenomas associated with cigarette smoking.

Methylenetetrahydrofolate reductase polymorphism and risk of colorectal adenomas.

A homozygous mutation at bp 677 in the gene for the methylenetetrahydrofolate reductase (MTHFR) was previously shown to be associated with a decreased risk of colorectal cancer. We examined the relation between the MTHFR genetic polymorphism and risk of colorectal adenoma in Japanese men using 205 cases of colorectal adenomas and 220 controls of normal total colonoscopy. The homozygous mutation was not measurably associated with colorectal adenomas. The findings corroborate the lack of an association between the MTHFR genotype and colorectal adenomas, but do not deny the possibility that the genotype may be involved in the late stage of colorectal carcinogenesis.

Osteoporosis and years since menopause.

In Fukuoka Prefecture, in south-western Japan, a regional screening program for osteoporosis was conducted from 1994 to 1995. The screening level in the bone mineral density (BMD) at the distal non-dominant radius was equal to or less than two standard deviations below age-specific mean (< or = -2.0 SD). In 1177 examinees with natural menopause (mean age: 61.4, range: 42-88), 56 of those who were screened were subsequently radiologically confirmed by orthopedic specialists to have osteoporosis (case group). They were then compared with 802 normal BMD (> or =-1.0 SD) women (reference group) with their lifestyle and reproductive characteristics. The adjusted odds ratio (OR) and its 95% confidence interval (CI) were calculated using a logistic regression model. A significant increase in the ORs for osteoporosis based on the number of years since menopause was observed for 7-13 years since menopause (OR = 2.3; 95% CI: 1.0-5.4) compared with <7 years, however, no increasing trend in risk was evident in 14+ years since menopause (OR = 1.4; 95% CI: 0.4-5.1). Thus, the elevated risk continued up to around 10 years since menopause. These findings are consistent with previous studies that reported an alternation in the calcium metabolism and bone loss related to the length of time after menopause. Both the childhood and current milk consumption were also associated with a decreased risk: ORs were 0.4 (95% CI: 0.2-0.9) and 0.5 (95% CI: 0.3-1.0), respectively.

Obesity, weight gain and risk of colon adenomas in Japanese men.

Obesity has been related to increased risk of colon cancer or adenomas, but the epidemiologic findings are not entirely consistent. We examined the relation of not only body mass index (BMI) but also waist-to-hip ratio (WHR) and weight gain to colon adenoma risk in men who received a preretirement health examination at the Japan Self Defense Forces (SDF) Fukuoka and Kumamoto Hospitals during the period from 1995 to 1996. In the series of 803 men at age 47-55 years, 189 cases of colon adenomas and 226 controls with normal total colonoscopy were identified. Weight at 10 years before was ascertained by referring to the recorded data. After allowance for hospital, rank in the SDF, smoking and alcohol use, weight gain over the past 10 years was significantly associated with increased risk of colon adenomas (odds ratio for > or = 6 kg versus < or =-2 kg = 2.2; 95% confidence interval 1.0-4.8). High BMI and high WHR were each associated with increased risk, but only WHR was related to the risk independently of weight gain. In particular, weight gain accompanied with a high WHR was associated with a significant increase in the risk. Men with high physical activity tended to have lower risk. Associations with obesity-related variables and physical activity were not materially differential as regards the location and size of adenoma. The findings indicate that weight gain in middle age leading to abdominal obesity increases the risk of colon adenomas, and consequently of colon cancer.

Prospective cohort study of risk factors for primary liver cancer in Hiroshima and Nagasaki, Japan.

We investigated risk factors for primary liver cancer among a cohort of 36,133 residents in Hiroshima and Nagasaki, Japan, originally established to examine the association between exposure to atomic bomb radiation and disease. A mail survey to study the late effects of atomic bomb radiation was conducted among the cohort between 1978 and 1981. During the subsequent follow-up period (average 8.61 years), 242 cases of primary liver cancer were identified through population-based tumor registries in the two cities. The relative risk (RR) of liver cancer was 2.23 [95% confidence interval (CI) = 1.53-3.23] for tobacco smokers compared with those who had never smoked. Alcohol use was slightly positively associated with the risk of liver cancer, and men who had quit drinking had an RR of 2.33 (95% CI = 1.34-4.07) compared with those who never drank. Among alcohol drinkers, an inverse relation between years of abstinence and the rate of liver cancer was found, possibly attributable to a confounding effect of preclinical disease. The use of female hormone preparations was modestly associated with the risk of liver cancer (RR = 1.29; 95% CI = 0.59-2.84). Other risk factors included a self-reported history of radiation therapy (RR = 1.79; 95% CI = 1.31-2.43).

Relationship between the amount of rice oil ingested by patients with yusho and their subjective symptoms.

The goal of this study was to clarify the subjective symptoms closely related to yusho by examining the relationship between the amount of PCB-contaminated rice oil ingested by patients and the subjective symptoms recorded on their questionnaires. The amount of PCB-contaminated rice oil consumed by the patients was obtained by interviewing the housewife in each yusho family. Individual consumption of the oil was estimated by taking into account age, sex and the number of meals at home. In 1970, 46 patients were available for analysis, and in 1971, 33 patients were available. Among 12 subjective symptoms studied, numbness of the limbs, coughing, expectoration, and the sensation of "elevated" teeth were considered to show a dose-response relationship, which suggests that these subjective symptoms are closely related to yusho. Consistent high rates of complaints of general fatigue and eye discharge were considered possibly to be connected with yusho, although no dose-response relationships have been determined. Other subjective symptoms, such as fever, headache, dizziness, abdominal pain, swelling in the joints, changes in menstruation, and loss of hair failed to show consistent dose-response relationships. It should be noted, however, that for these symptoms which failed to show dose-response relationships, it is impossible to deny a causal relationship.