The number of children suffering from mental disorders and health problems such as allergies and asthma has risen sharply over the past decade in this country.
The United States and European countries are also facing the increasingly serious problems of premature births and childhood obesity, in addition to allergic reactions.
Many experts say the rise in health problems involving children is related to the use of chemicals in our daily lives and the impact of medical treatment provided to the children's mothers.
Moves are on the rise at home and abroad toward finding measures to protect children from the health hazards of harmful chemicals in the living environment. Known as "children's studies," the moves are designed to better inform the public of ways to improve conditions relevant to children's health by improving communication between experts and ordinary citizens.
In an average household in an industrially advanced country, family members are affluent enough to eat and drink whatever they like.
It would seem that families like this have nothing to worry about in their daily lives. But an increasing number of children suffer from a wide range of physical irregularities, including rashes and chronic coughing.
Some of the suspected causes of these problems are organic solvent vapors emitted by new homes and furniture, food additives and chemicals contained in food wrappers.
According to a recent survey by the Education, Science and Technology Ministry, the number of cases of asthma among kindergartners and primary school students has more than doubled in a little more than a decade.
One of every four primary school students is affected by atopic dermatitis, another survey shows, while the number of bronchial asthma cases among children has doubled in the past decade.
No specific cause for any of these diseases has been determined yet.
But recent advances in technology, including in techniques to measure minute substances in the environment, have led to increased knowledge in the field. New findings indicate that health hazards for children may be linked not only to such confirmed pollutants as dioxins and polychlorinated biphenyl (PCBs), but also to minute amounts of chemicals in food and in the air.
Since children have a higher sensitivity to chemical substances than adults, they react accordingly. In addition, since the volume of air per breath in comparison with body weight is larger for children than adults, children are more susceptible to inhaled pollutants, according to experts.
They can also unknowingly absorb chemicals that permeate the wrappings of the sweets they consume almost every day, the experts said.
The experts also noted that pollutants that accumulate easily in the body, such as dioxins and PCBs, can be transmitted to an embryo via the mother's umbilical cord. Babies also can be affected by harmful substances in the breast milk of their mothers.
If affected by chemical substances during the embryonic period or infancy, children run a higher risk of disease and developmental abnormalities.
The number of premature babies and babies born severely underweight has been increasing in the United States and Europe, and "lifestyle diseases," such as high blood pressure, diabetes, asthma and obesity, are on the rise in children as well as in adults.
One report said children born to poor, underfed mothers tended to become overweight.
The use of steroids by women is known to boost the risk of premature delivery, and such children have a higher possibility of developing high blood pressure, diabetes and other diseases in the future.
Medical expenses for children with health problems, including those with learning disabilities, are estimated to be as high as 10 billion dollars a year in the United States, posing a major social problem.
The U.S. National Institutes of Health has launched a 1 billion dollars national project to explore the causes of children's diseases and how to prevent them. Named the National Children's Study, the project is aimed at examining about 100 children from before birth to age 21, with the final report scheduled to be finished by 2009. The NIH project has drawn much attention from the World Health Organization and European experts.
In Japan, the Environment Ministry embarked on a program last year to formulate a reliable health hazard measurement method, with the aim of studying the influences of chemicals on the health of children.
The conventional method is for use exclusively with adults and is based on experiments on animals. The ministry's program is expected to shed light on what should be done to control and prevent health problems in children.
The postgraduate school of the medical department of Chiba University is set to launch a project in April in the hope of undertaking a Japanese version of the NIH National Children's Study program.
Named the "Next-generation environmental health studies project," the university plans to address the problems of children's health in a systematic way, with researchers in such diverse fields as internal medicine, pediatrics, dermatology, obstetrics and gynecology, and otorhinology all participating by eliminating barriers between the different schools of the university, such as the medical, pharmacology and nursing schools.
The Chiba University team will tackle the challenges of discovering the mechanisms of disease development and methods for the early diagnosis of diseases, in addition to pioneering a new field of medical science referred to as environmental disease preventive medicine.
The envisioned field is aimed at boosting the spread of research findings to the general public and providing people with information about health hazards in simple language to help them improve their lifestyle. The new field also will undertake the task of conveying feedback from children and other members of society to medical researchers.
Since the envisaged field requires communication between medical experts and the public, the Chiba University team has taken a joint medicine-mass media approach, calling for cooperation not only from medical experts, but also from experienced reporters from newspapers, television and other news media.
In the United States, a survey of more than 3,000 people showed that in many cases people were found to have a better chance of avoiding diabetes by changing their lifestyle, such as diet, weight control and exercise, than by taking medicine. The findings have been published in the New England Journal of Medicine and other medical magazines.
Finding a cure for patients is the doctor's job, but when it comes to preventive medicine, cooperation from the general public is required.
This task is not limited to the health problems of children alone.
Medical services that cater to the socially weak are also indispensible for the aged.
High hopes are therefore placed on the Chiba University project, since its envisioned field of medicine is one that Japan, with its rapidly graying society and low birth rate, will find useful.