Intake ratio of water-insoluble dietary fiber to the water-soluble one in Japanese: an estimation on dietary records and the secular consideration on the national nutrition survey.

Thirty-four foods were analyzed in order to determine the content of water-soluble dietary fiber (SDF) and insoluble dietary fiber (IDF). Using the results with the standard table for 227 foods, the intake ratio of IDF/SDF of an average Japanese was calculated for the period 1946-1990. The ratio was 3.22 in 1990 as calculated on the food intakes shown in the national nutrition survey, and the secular change was not detected since 1946 when the ratio was 3.30. The ratio was also shown to be well preserved between types of households including the age of the head. Using dietary records of 60 healthy city workers (average 42.8 years) for 4 weeks, however, the weekly average ratio for an individual was found to vary in the range of 2.25-5.13 although the total average for 60 individuals was 3.33. Thus, the well preserved IDF/SDF intake ratio for an average Japanese showed, on the contrary, a wide variation of food selection between each person.

Age, period and cohort analysis of trends in mortality from major diseases in Japan, 1955 to 1979: peculiarity of the cohort born in the early Showa Era.

Japanese researchers have reported that recent mortality rates from diabetes mellitus, ischemic heart disease, peptic ulcer, cirrhosis of the liver and suicide for middle-aged Japanese men have increased by comparison with those for other age groups. There has been some controversy over the etiology of this unusual trend, and in particular whether it is due primarily to recent undesirable socio-economic factors (period effects) or to factors specific to these cohorts born in the early Showa Era, around 1925 to 1940 (cohort effects). A possible source of this controversy lies in the methods which have been used to describe the trends; these are mostly descriptive and graphical. To elucidate which factors are responsible for these trends, we analysed the mortality data quantitatively applying an age-period-cohort model modified so that period effects remain constant within certain age groups but may vary from one age group to the next. Although the identifiability problem still occurs in the modified model, estimable curvature components of time effects may be used to examine these unusual trends. In fact, the peculiarity of the cohort born in the early Showa Era was clearly detected by the curvature components of cohort effects for these major diseases. These findings are consistent with the 'cohort hypothesis' for the recent peculiar trend in Japanese male mortality.

A quantitative study of physiological cerebral atrophy with aging. A statistical analysis of the normal range.

A new method of discriminating pathological cerebral atrophy from physiological atrophy during aging is reported. The authors advocate a pixel counting method using a minicomputer for the quantitative measurement of cerebral atrophy. Five hundred cases were studied with this quantitative method and the normal range of the physiological atrophy was determined statistically. In order to estimate the degree of cerebral atrophy easily, the conventional linear measurement methods were compared with the pixel counting method using multivariant analysis, and a simple formula for the calculation of the degree of cerebral atrophy is proposed. Using this formula and the normal range, pathological cerebral atrophy is easily detectable.

[The normal range of cerebral atrophy during aging: statistical analysis of 500 normal subjects].

We previously reported the newly developed quantitative measurement of the cerebral atrophy (pixel count method), and advocated the value CCR (CSF-cranial ratio) as the index of the volumetric measurement of the cerebral atrophy. As the pixel count method is somewhat troublesome, we tried to compare the various linear measurement methods with pixel count method by means of multivariant analysis, and reported a single formula to calculate CCR from the linear measurement methods. Now we studied 500 normal subjects using the pixel count method and examined the normal range of the cerebral atrophy during aging by means of the maximum likelihood method. The normal range was estimated as follows; 0.32 less than y less than 5.78 (t less than 48), 0.068 t--2.944 less than y less than 0.368 t--11.884 (t greater than 48). Using these formula and this newly reported normal range, we can easily predict whether the cerebral atrophy is pathological or not.

[A quantitative study of brain atrophy on computed tomography--multivariate analysis for comparison between the linear measurement method and the pixel count method].

We previously reported the newly developed quantitative measurement of the cerebral atrophy. The data indicated that the volume of the cerebrospinal fluid not always gradually increases during the life course but remains relatively constant until age 50 and thereafter increases with a wide variation. Though the technique, which is called the pixel count method, is highly quantitative, it is quite troublesome as it needs the computer to count out each pixels. On the other hand, the linear measurement method is easier than the pixel count method, but is far less quantitative. We examined seventy four subjects using both the linear measurement method and the pixel count method, and compared them by means of the multivariant analysis. Three different linear measurement methods were selected by the stepwise multiple regression analysis, those are B (distance between the caudate nuclei), E (greatest distance between the lateral ventricles at the level of the cella media) and G (number of visible sulci whose width are more than 3.1 mm at the level of 3 cm above the corpus callosum). B and E were calibrated by the maximum internal width of the skull (H). The highest correlation was achieved with a formula employing these parameters as follows; y = 42.66 X B/H + 12.52 X E/H + 0.232 X G - 2.92 (y means the estimated value of the CCR (CSF-cranial ratio), which is obtained by dividing the CSF volume by the cranial cavity). Multiple correlation coefficient was 0.76, and was statistically significant (p less than 0.001). The authors emphasized that using this formula we can easily predict CCR as the index of the brain atrophy without any computer.

South-to-north gradient in distribution of the r determinant of hepatitis B surface antigen in Japan.

A total of 2.305 sera positive for hepatitis B surface antigen were obtained from asymptomatic carriers throughout Japan and subtyped for the d, y, w, and r specificities by the hemagglutination inhibition method. Determinant d prevailed in Japan (d, 99.1%; y, 0.9%), and there was no regional variation in its occurrence. In sharp contrast, there was a marked variation in the distribution of the w and r determinants, forming an apparent south-to-north gradient of r. The percentage of r determinant was highest in Kyushu (92%-94%); it decreased gradually along the axis of Japan to the north and was lowest in Akita (46%), which is located at the north end of Honshu.