Naomasa Sakamoto

Dietary risk factors for inflammatory bowel disease A Multicenter Case‐Control Study in Japan

&NA; To evaluate the role of dietary factors in the etiology of inflammatory bowel disease (IBD), we conducted a multicenter hospital‐based case‐control study in a Japanese population. Cases were IBD patients aged 15 to 34 years [ulcerative colitis (UC) 111 patients; Crohns disease (CD) 128 patients] within 3 years after diagnosis in 13 hospitals. One control subject was recruited for each case who was matched for sex, age, and hospital. A semiquantitative food frequency questionnaire was used to estimate preillness intakes of food groups and nutrients. All the available control subjects (n = 219) were pooled, and unconditional logistic models were applied to calculate odds ratios (ORs). In the food groups, a higher consumption of sweets was positively associated with UC risk [OR for the highest versus lowest quartile, 2.86; 95% confidence interval (CI), 1.24 to 6.57], whereas the consumption of sugars and sweeteners (OR, 2.12; 95% CI, 1.08 to 4.17), sweets (OR, 2.83; 95% CI, 1.38 to 5.83), fats and oils (OR, 2.64; 95% CI, 1.29 to 5.39), and fish and shellfish (OR, 2.41; 95% CI, 1.18‐4.89) were positively associated with CD risk. In respect to nutrients, the intake of vitamin C (OR, 0.45; 95% CI, 0.21 to 0.99) was negatively related to UC risk, while the intake of total fat (OR, 2.86; 95% CI, 1.39 to 5.90), monounsaturated fatty acids (OR, 2.49; 95% CI, 1.23 to 5.03) and polyunsaturated fatty acids (OR, 2.31; 95% CI, 1.12 to 4.79), vitamin E (OR, 3.23; 95% CI, 1.45 to 7.17), and n‐3 (OR, 3.24; 95% CI, 1.52 to 6.88) and n‐6 fatty acids (OR, 2.57; 95% CI, 1.24 to 5.32) was positively associated with CD risk. Although this study suffers from the shortcoming of recall bias, which is inherent in most retrospective studies (prospective studies are warranted to confirm the associations between diet and IBD risk), the present findings suggest the importance of dietary factors for IBD prevention.

Dietary habits and risk of ossification of the posterior longitudinal ligaments of the spine (OPLL); findings from a case-control study in Japan.

The relation between dietary habits and the risk of ossification of the posterior longitudinal ligaments of the spine (OPLL) was investigated in a case-control study conducted in Japan from 1998 to 2001. Prevalent OPLL cases (n = 69) were identified and individually matched by age and sex with community controls (n = 138) randomly selected from the general population in Hokkaido. A self-administered food-frequency questionnaire was used to assess habitual dietary intake. The odds ratio (OR) and its 95% confidence interval (CI) were estimated, using conditional logistic regression models to compute the OR adjusted for a history of diabetes mellitus. We found that frequent consumption of pickles (salted products) was significantly associated with an increased risk of OPLL, with an adjusted OR of 1.6 (95% CI, 1.1 to 2.2). The adjusted OR for nondaily consumers of rice was 3.0 (95% CI, 2.4 to 3.7). Frequent consumption of chicken (adjusted OR, 0.5; 95% CI, 0.3 to 0.98) and soy foods (adjusted OR, 0.4; 95% CI, 0.2 to 0.7) was significantly associated with a decreased risk of OPLL. Our findings suggest that dietary habits may constitute independent risk factors for OPLL. Further studies will be needed to prospectively determine the relationship between dietary habits and OPLL risk.

High body mass index after age 20 and diabetes mellitus are independent risk factors for ossification of the posterior longitudinal ligament of the spine in Japanese subjects: a case-control study in multiple hospitals.

Study Design. A sex- and age-matched case-control study was carried out. Objectives. To facilitate early prediction, prevention, and treatment of ossification of the posterior longitudinal ligament of the spine, the authors analyzed histories of past illness, past body mass indexes, and body pliableness by nature, adjusted for other factors considered to be risk factors. Summary of Background Data. The cause of ossification of the posterior longitudinal ligament of the spine has not yet been elucidated in detail, although many possible causative factors have been suggested, including gender, diabetes mellitus, trauma, hormonal imbalance, and dietary habits. Methods: A self-administered questionnaire was obtained from 69 patients with ossification of the posterior longitudinal ligament of the spine and 138 sex- and age-matched control participants who were free of spinal disease, randomly selected from participants in a health checkup in a town. After univariate analysis, a stepwise method was applied to select significant factors in multivariate analysis. Results. A multivariate analysis revealed that the following three indicators were independent potent risk factors for ossification of the posterior longitudinal ligament of the spine: history of diabetes mellitus, history of lumbago, and maximum body mass index before manifestation ≥25, after adjustment for other possible lifestyle risk factors. Conclusion. Excessive weight gain between 20 and 40 years of age, diabetes mellitus, and lumbago were found to be independent risk factors for ossification of the posterior longitudinal ligament of the spine. Follow-up studies, including the addition of hospital-based control participants and analysis of genetic polymorphisms, will be needed in the future.

Lifestyle factors and risk of amyotrophic lateral sclerosis: a case-control study in Japan.

PURPOSE We examined the associations between lifestyle factors and the risk of amyotrophic lateral sclerosis (ALS) using a case-control study in Aichi Prefecture, Japan. METHODS The study comprised 183 ALS patients diagnosed by the El Escorial World Federation of Neurology criteria as well as 366 gender- and age-matched controls randomly selected from the general population with the use of the basic register of residents. Detailed information on lifestyle factors was obtained through a mailed self-administered questionnaire. The strength of association between ALS and a potential risk factor was assessed by calculating odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS Vigorous physical activity, self reported stress, a type A behavior pattern, and less frequent intakes of green-yellow vegetables were significantly associated with increased risk of ALS, whereas smoking and drinking habits were not. The greatest effect on risk for ALS was posed by the combination of a type A behavior pattern and less frequent intakes of green-yellow vegetables (adjusted OR, 11.2; 95% CI, 3.8 to 33.0). CONCLUSION These data suggested that imbalances between excessive productions of oxidants as patient-specific factors and a diminished or missing antioxidant defense system in motor neurons may increase the risk of ALS.

Nutritional status and risk of amyotrophic lateral sclerosis in Japan

Only a few human studies have reported the relationship between dietary factors and the risk of amyotrophic lateral sclerosis (ALS). We therefore analyzed the relationship between macronutrients (carbohydrate, protein and fat) and the risk of ALS using a case‐control study in Japan. The study comprised 153 ALS patients diagnosed by the El Escorial World Federation of Neurology criteria, and 306 gender‐ and age‐ matched controls randomly selected from the general population. A self‐administered food frequency questionnaire was used to estimate pre‐illness intakes of food groups and nutrients. The strength of association between ALS and a potential risk factor was assessed by calculating odds ratios (ORs) and 95% confidence intervals (CIs). A high intake of carbohydrate was significantly associated with an increased risk of ALS (adjusted OR = 2.14, 95% CI 1.05–4.36; the highest versus the lowest tertile). ORs for the second and third tertile of total fat were 0.57 and 0.41 (95% CI 0.21–0.80), respectively. ORs for the highest tertile of intake versus the lowest were 0.41 (95% CI 0.21–0.80) for total fat, 0.30 (95% CI 0.16–0.5) for saturated fatty acids (SFAs), 0.35 (95% CI 0.18–0.69) for monounsaturated fatty acids (MUFAs) and 0.58 (95%CI 0.40–0.96) for polyunsaturated fatty acids (PUFAs). Our findings suggest that high intakes of carbohydrate and low intakes of fat and some kinds of fatty acids may, when combined, increased the risk of ALS.

Fruit and Vegetable Intake and Risk of Amyotrophic Lateral Sclerosis in Japan

Background: There has been little interest in the role of nutrition in the prevention of amyotrophic lateral sclerosis (ALS). We investigated the relationship between dietary intake of vegetables, fruit, and antioxidants and the risk of ALS in Japan. Methods: Between 2000 and 2004, we recruited 153 ALS patients aged 18–81 years with disease duration of 3 years within the study period in accordance with El Escorial World Federation of Neurology criteria. Three hundred and six gender- and age-matched controls were randomly selected from the general population. Information on dietary factors was collected using a validated self-administered diet history questionnaire. Results: A higher consumption of all fruits and vegetables and fruit alone in the highest quartiles was associated with a statistically significantly reduced risk of ALS. Although not statistically significant, a beneficial association between intake of all vegetables, green and yellow vegetables and other vegetables and ALS was found. No statistically significant dose-response relationship was observed between intake of β-carotene, vitamin C and vitamin E and the risk of ALS. Conclusion: Our findings suggest that higher intake of food rich in antioxidants such as fruit and vegetables confer protection against the development of ALS.

Case‐control study of medical history and idiopathic pulmonary fibrosis in Japan

Objectives:  A few epidemiological studies have indicated that a patients past medical history may contribute to the risk of developing idiopathic pulmonary fibrosis (IPF). A relationship between a history of selected disorders and the risk of IPF was assessed in a multicentre hospital‐based case‐control study in Japan.

FokI variant of vitamin D receptor gene and factors related to atherosclerosis associated with ossification of the posterior longitudinal ligament of the spine: a multi-hospital case-control study.

Study Design. A sex- and age-matched case-control study with genotyping of the FokI variant of the vitamin D receptor gene (VDR) was carried out. Objectives. To facilitate the early prediction, prevention, and treatment of ossification of the posterior longitudinal ligament (OPLL) of the spine, we analyzed the FokI variant of VDR and past body mass indexes, histories of past illness, family history, and body pliability along with lifestyle factors. Summary of Background Data. Many possible genetic and environmental risk factors for OPLL have been suggested, including male sex, high body mass index, diabetes mellitus, trauma, hormonal imbalance, and dietary and sleeping habits and genetic variants. Methods. Both a self-administered questionnaire and whole blood samples were obtained from 63 patients with OPLL and 126 sex-, age-, and hospital-matched controls free of backbone diseases were randomly selected from hospital patients. VDR genotyping was carried out using PCR-RFLP methods. After univariate analysis, multivariate and subgroup analyses according to the VDR genotype was applied to clarify the confounding relationship between VDR genotype and other possible risk factors. Results. A multivariate analysis revealed that the VDR FF genotype, family history of myocardial infarction, high body mass index at age 40, long working hours, and working with night shift to be independent potent risk factors for OPLL. Conclusion. The risk of developing OPLL may possibly be reduced gradually and effectively by removing or minimizing the effect of such lifestyle factors one at a time through targeted preventive intervention.

Effects of eicosapentaenoic acid intake on plasma fibrinolytic and coagulation activity by using physical load in the young.

To assess the effect of eicosapentaenoic acid (EPA) intake on fibrinolysis and coagulation, 30 male subjects, approximately 19-23 y old, were examined for plasma fibrinolytic and coagulation activity by using a bicycle ergometer load (90 W, 20 min) before and after EPA intake of 1.125 g/d for 2 wk. Because of the EPA intake, the fibrinolytic activity was promoted, the plasmin-alpha 2 plasmininhibitor complex (PIC) level was decreased by 16.7%, and the thrombin-antithrombin III complex (TAT) level was increased by 75.4%; conversely, the D-dimer of the fibrin degradation peptide (D-dimer) level did not change from that before EPA intake. By the physical load, 1 h after ingesting the load, the PIC level was significantly decreased by 26.7%, the TAT level was significantly increased by 51.1%, and the D-dimer level was significantly decreased by 24% in comparison with levels before EPA intake. Thus, as determined by the load, a small amount of daily EPA intake clearly decreased fibrinolytic activity and increased coagulation activity. One hour after a physical load, the rate of change of the gamma-glutamyl transpeptidase (gamma-GTP) level correlated significantly and negatively to the rate of change in the PIC and TAT levels. Thus, EPA intake may affect liver and kidney function. EPA intake decreased systolic blood pressure by 5 mmHg and diastolic blood pressure by 10 mmHg.

The effect of diet on blood vitamin K status and urinary mineral excretion assessed by a food questionnaire

To assess Vitamin K (VK) status by food questionnaire, healthy young males (32) and females (9) were given a food list of 50 VK rich foods (identified in the 4th edition standard tables of food composition in Japan). After checking the food names and approximate amount eaten for 7 days, early morning blood and urine samples were collected. Prothrombin and hepaplastin was tested and plasma protein induced by VK absence factor II (PIVKA-II), osteocalcin, and calcium, phosphorous and magnesium in plasma and urine were determined. Participants who have a habit of eating natto, a traditional Japanese food very rich in Vitamin K, VK were excluded, and lowest and highest VK consumers were compared (males; lowest 7 vs. highest 7, females; 3 vs. 3). Plasma PIVKA-II levels, and urinary calcium and magnesium excretion of the lowest was significantly higher, but urinary phosphorus was lower, than that of the highest in females. In the natto eaters, daily mean VK intakes and hepaplastin test results of natto eaters were significantly higher, but urinary calcium excretions were lower than that of non natto eaters in males. These results suggest that Daily VK intake estimated from a questionnaire, is well related to real VK status, and also that natto is a good dietary source of vitamin K.