Kazushi Okamoto

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.

Comparability of epidemiological information between self- and interviewer-administered questionnaires

The aim of the present study was to determine the extent to which respondents provided the same answers to a health-related lifestyle questionnaire in self- and interviewer-administered forms. A total of 234 subjects completed a 110-item questionnaire in both interviewer and self-administered forms. Modes of administration were separated by a 2-week interval. The order was determined by random allocation. The presence and the extent of the tendency to give socially acceptable responses were evaluated using percentage of bias calculated as the ratio of the difference in proportion of positive responses or the mean between interviews and questionnaires and those in questionnaires. All percentages of bias were in the positive direction, ranging from 1.4% (physical exercise) to 26.1% (general life stress). The average percentage of bias was higher in women than in men and were stronger for younger respondents. The age differences between interviewer and respondent were inversely and most strongly related to percentage of bias. Self- and interviewer-administered questionnaires yield very similar results in discriminating between subjects, but the interviewer-administered questionnaire showed systematically more desirable responses to questions related to lifestyle factors. The differences in characteristics between interviewer and respondent may be important determinants of the socially desirability bias in the interview.

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.

Family History and Risk of Subarachnoid Hemorrhage. A Case-Control Study in Nagoya, Japan

Background and Purpose— We sought to examine the relation between a family history of subarachnoid hemorrhage (SAH) and the risk of SAH by using a case-control study. Methods— Case subjects consisted of a consecutive series of 195 patients with spontaneous SAH, aged 30 to79 years, with aneurysms confirmed by angiography and/or CT scan. Hospital and community control subjects were identified and matched to each case by sex and age (±2 years). Multiple conditional logistic regression was used to calculate the odds ratio (OR) and 95% interval (CI) adjusted for potential confounders. Results— Having a family member with SAH was significantly associated with an increased risk of SAH (OR, 4.0, 95% CI, 2.0 to 8.0), after adjusting for potential confounders. The risk for a positive family history of SAH was similar for men and women and was inversely related to the SAH patient’s age. A maternal positive SAH history (OR, 5.4; 95% CI, 1.8 to 16.0) posed a much greater risk than a paternal positive history (OR, 3.2, 95% CI, 1.1 to 13.4). Conclusions— A positive family history of SAH was significantly and strongly associated with the risk of SAH. To prevent the onset of SAH at a younger age, much more attention should be given to individuals with any family member (first-degree relatives) suffering SAH episodes.

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.

Emotional support from family members and subjective health in caregivers of the frail elderly at home in Japan.

This study sought to determine the factors associated with subjective health in caregivers of the frail elderly living at home, using multivariate regression analysis. Data were collected from 130 caregivers of frail elderly persons listed on a roster for utilization of day service or short stay service from two Home Visit Nursing Care Stations, using self-administered questionnaire from January to February of 2005. Family caregivers were defined as co-residents family members who provided a minimum of 1 h of daily care for at least 3 months. Multiple logistic regression analysis was performed to examine the factors associated with subjective health in caregivers of the frail elderly at home. Subjects with good health had less depressive symptom (p=0.001), much emotional support (p=0.003) and low caregiver burden (p=0.03). Multivariate logistic regression analysis showed good health had a significantly positive association with only much emotional support after adjustment for confounders. Of the total effect of emotional support on subjective health, the direct effect (84.7%) was much greater than the indirect effect (15.3%). Results indicate that much emotional support from family member for caregiver is essential for better subjective health in caregivers.