The bright lights of the city are drawing a record number of people in search of careers and excitement. But city life comes at a price. Recent studies have found that Japan's city dwellers are jeopardizing their lives and their offspring.

While Japanese people have been living longer and longer to keep the lead in the world's longevity race as a country, the growth in life expectancy has apparently hit the ceiling in big cities. Tanji Hoshi, professor of public health at Tokyo Metropolitan University, has found that Tokyo residents, who outlived people in other regions until the early 1980s, now have a much shorter lifespan than those of other prefectures.

For example, the life expectancy of Tokyo residents increased 7.07 years from 69.84 to 76.91 for men between 1965 and 1995. But during this period, men in Nagano Prefecture gained 9.86 from 68.45 to 78.08. As a result, Nagano men became the longest-lived Japanese males in 1995 while the ranking of Tokyo men dropped to 20th.

Tokyo women, who ranked first in life expectancy in 1965 at 74.7, meanwhile lost ground to rate a poor 33rd in 1995 with 83.12. On the contrary, Kumamoto women, formerly rated 29th, came in second at 84.39.

The 1965 data demonstrated an overall trend that people in industrialized regions, such as Tokyo, Kyoto and Kanagawa, with higher incomes and access to better health care, lived longer than people in the countryside. Now, 30 years later, that trend has reversed.

"And the disparity between city and country is expanding every year," Hoshi says. "That's really serious."

Hoshi and his research team are paying particular attention to middle-aged men. Their analysis of Tokyo population statistics showed that the mortality rate for older-generation men (45-59 years old) is 10 percent higher than the national average.

Further research is needed to explain the ruin of Tokyo's once-high life expectancy, Hoshi says, but he believes that polluted air, contaminated water and stressful lifestyles play significant parts.

"Since Japan does not have the big income gaps that other countries have, I think environmental factors are more important than social factors," Hoshi says.

Indeed, the research group found that within Tokyo itself, the mortality rate from cancer is much lower in relatively green western Tokyo than in central Tokyo. In other prefectures also, life expectancy is lowest in downtown areas and increases as research points move upstream.

Where the boys aren't

Polluted air and water may also undermine city dwellers' reproductive health. A recent study of governmental population statistics for the last 24 years indicated that city mothers bear fewer boys than country mothers.

A Tokyo-based nongovernmental organization, the People's Association on Countermeasures to Dioxin and Endocrine Disrupters, found that male births as a percentage of total births have apparently declined in places that underwent rapid urbanization and industrialization.

Historically about 107 boys have been born for every 100 girls in Japan. This means 51.6 percent of all newborns were boys. Between 1974-81, nearly 70 percent of prefectures reported figures close to 51.6. The figures for 1990-97, however, show the number of prefectures with a statistically significantly lower rate of newborn males doubled to 60 percent, with Ishikawa Prefecture showing the lowest rate at 50.9.

The trend shows boys missing in regions with large populations, many factories, heavily trafficked roads, incinerators and waste dumping sites. For example, in Kanagawa and Saitama prefectures, the ratio of boys to girls was particularly low in big cities such as Yokohama, Kawasaki and Omiya. Tokyo has also deviated from the norm throughout the period of study, coming in at 51.4 for the most recent period.

Northeast Nara Prefecture, much less densely populated but the location of many industrial waste disposal sites, where abnormal levels of heavy metals such as cadmium and lead have been found in the rivers, also showed a low ratio of boy babies; one town hit a surprising 47.5 in 1990-97.

Declines in the ratio of boy babies have been reported in many countries. Researchers cite many possible reasons for the trend -- everything from age differences between parents to less-frequent intercourse. Environmentalists argue, however, that the pattern is clearly linked to exposure to hormone-disrupting chemicals. Citing the example of Italy's Seveso, where a striking falloff of male newborns -- to 35.1 percent -- was observed after a chemical plant explosion in 1976 released high levels of dioxin into the atmosphere, they claim that endocrine disrupters such as dioxin released from waste disposal sites and incinerators upset men's ability to produce sperm.

Michiko Kamiyama, lawyer and a member of the association who compiled the report, takes a cautious stance, saying that the data only brings up the need for further investigation. But she also points out that there are many ominous signs that indicate chemicals in the environment are upsetting people's reproduction.

"Analysis of low birth weights, birth rates and miscarriages is also necessary," Kamiyama says. "We hope researchers, experts and the government will take our data seriously and undertake a major research project on this issue."

"People do not immediately die from pollutants like endocrine disrupters, so the current life span disparity may reflect past exposure to pollution," Hoshi points out. "With the decline in land prices people have recently returned to live in central Tokyo, but [in terms of health] Tokyo may not be a good place to live."