In mid-May 1988 ocular troubles occurred in many children in several schools. We suspected them to be victims of a mass outbreak of allergic conjunctivitis induced by grass pollen from clinical and epidemiological observation. We have investigated the matter and taken measures to solve the problem.
The schools in which ocular troubles occurred are in an urbanized rural region in Kanagawa Prefecture. An on-the-spot study found the schools are surrounded by rice fields. When the troubles occurred in May the grass for cattle grew densely on the fields and was just in full bloom. This grass, known as Italian ryegrass (Lolium multiflorum), was planted eleven dairy farmers who borrowed the fields.
Some data were collected from the health records in the schools. And some were collected by the questionnaires taken when children came to the nurse's office of the school to treat their conjunctivitis. It was irevealed that similar troubles had occurred around mid-May every year. In other seasons, the incident of conjunctivitis is sporadic. More than 100 children suffer from acute allergic symptoms every year. Inflammation manifests itself from late morning to early afternoon in windy warm days in mid-May and about half of the cases occur when they were outdoors. Symptoms of which children most frequently complained were eye itching and hyperemia in the conjunctiva. Other symptoms include tearing, nasal discharge, eye pain and swelling. Over 50% of the children suffered from them. In serious cases sclera was swollen forward as compared with cornea and looked like geratin. A sticky discharge was found in about 20% of the patients.

Over the three years from 1980 to 1982, investigations were carried out into the living and working conditions of fishermen and farmers aged 30 to 59 in a coastal region of Chiba prefecture. The major findings are as follows:
(1) Man-years of work are less in the fishing communities than in the farming villages. Especially, women in the fishing communities work less.
(2) As for food intake, Fishing people consume larger amounts of fish and shellfish (animal protein) than farmers, while farmers eat a good deal of vegetables and rice compared with fishermen.
(3) Blood' tests revealed that hemoglobin, serum iron, total serum cholesterol, uric acid, GOT and GPT values are higher in fishermen than in farmers. HDL cholesterol levels were higher in the agrarian population. There was no great difference in serum protein, albumin, triglyceride, alkaliphosphatase, and cholinesterase levels.
(4) The obesity rate is higher in the fishing villages than in the farming villages. Especially the obesity incidence is notably high among women in the fishing communities.

Over the three years from 1980 to 1982, investigations were carried out into the health conditions of inhabitants aged 30 to 69 in rural regions of Chiba Prefecture.
The major findings are as follows:
(1) Significant sex differences exist for many blood test findings.
(2) Significant correlations are found among values of many blood test findings.
(3) These values are analyzed by principal component analysis and some factors are extracted. First of them is found both men and women in all districts similarly and is identified as something of nutritional condition.