An attempt was made to correct variations in the measurement of total cholesterol levels in order to study year-by-year trends in the values of total cholesterol measured at our center as part of the mass health screening project.
The sutudy covered the period from 1979 to 1996.
In coming to grips with variations in the measurement, we used the month-specific means of in-house pooled serum, which is internal quality control serum. On the basis of. the in-house pooled serum, the use of which began in June 1993, we observed variations, while correcting variations between lots and computing the values of in-house pooled serum on one and the same level. Variations in the means of total cholesterol in the mass health screenings proved similar to those in the levels of measurement, suggesting that distortions in the measurement could be corrected. To compensate for the distortions, we computed conversion factors so that the vallues of the in-house pooled serum observed at one and the same level could be compatible with the levels of secondary certified reference material for the measurement of serum lipids and then used the factors to correct the age-specific means of total cholesterol recoreded in each year's mass health screenings.
The year-by-year trends in the values of total cholesterol were such that the period of 18 years witnessed a rise of about 10mg/dl among men and about 6mg/dl among women in the age bracket of 29 and under, about 18-20mg/dl among men and about 16-17mg/dl among women in that of 30-59, and about 10-13mg/dl both among men and women in that of 60 and over. There were signs that the pace of rises from 1991 on was slower than during the 1981-1990 period.

We have checked into the function of konjak, or the devil's-tongue (Hydrosme vivieri) to reduce cholesterol in order to cast light on its significance as a health food. We processed chipped glucomannan into crackers (hereinafter referred to as “mannan crackers”) and examined its impacts on lipid metabolism. Enrolled for this study were hospital staff members whose total cholesterol exceeded 200mg/dl and students boarding in the hospital's nursing college.
The findings attested to the fact that the intake of mannan crackers may serve to reduce the values of total cholesterol. The higher the value of total cholesterol before this study, the greater the drop. Since we could not detect any effect on either HDLcholesterol or triglyceride, the mannan crackers were considered capable of specifically reducing LDL-cholesterol. We observed no numerical changes in the complete blood cell count (CBCC) and blood chemistry, either. Some of the subjects had abdominal swelling, diarrhea and other digestive problems but theirs were not serious cases. Yet in another aspect, there was no difference in body weight between before and after this study, but the intake of energy and lipid dropped during the period, suggesting that the intake of mannan crackers would produce an effect on the dietary pattern. Having said that, konjak (mannan crackers) may be considered capable of directly or indirectly reducing cholesterol, particularly LDL-cholesterol, suggesting that mannan crackers are of significance as a health food.
The significance of this study for agriculture and rural community must not go unmarked. This study will contribute to the development of agriculture as an industry, while the farm product by the name of konjak has something to do for health, and will be instrumental in protecting the rural environment, not to mention the lives of farm workers engaged in its production. It is a task for us to grapple with by associating itself with farm work and rural villages with the close collaboration of those farm producers.