Journal Club 埼玉医科大学 総合医療センター 内分泌・糖尿病内科 Department of Endocrinology and Diabetes, Saitama Medical Center, Saitama Medical University 松田 昌文 Matsuda, Masafumi 2012 年 11 月 8 日 8:30-8:55 ８階 医局 Paik JM, Curhan GC, Taylor EN. Calcium intake and risk of primary hyperparathyroidism in women: prospective cohort study. BMJ Oct 17;345:e6390. doi: /bmj.e6390. Sakata R, McGale P, Grant EJ, Ozasa K, Peto R, Darby SC. Impact of smoking on mortality and life expectancy in Japanese smokers: a prospective cohort study. BMJ Oct 25;345:e7093. doi: /bmj.e7093.

Nurses' Health Study は 1976 年に Frank Speizer 医師が研究をはじめ、 そして the Nurses' Health Study II は 1989 年に Walter Willett 医師が研究 をはじめた。これは最も信頼がたかく、長期間にわたって行われた高 齢女性の健康に関する疫学研究である。 この研究は 121,700 人の女性看護師を登録しており、 1970 年半ばから 癌や心臓血管疾患のリスクファクターを調べるために行われた。 NHS は女性のメジャーな慢性疾患に関する調査としては、今までに行われ たもののなかでも最大級である。 Channing Laboratory の臨床家、疫学 者、統計学者が参加している。研究参加者は Massachusetts medical community(Harvard Medical School, Harvard School of Public Health, Brigham and Women's Hospital, Dana Farber Cancer Institute, Boston Children's Hospital, and Beth Israel Deaconess Medical Center ）の人 で構成されている。 1980 年からは食事の評価、アスピリンの使用、大 腸の検査の項目がもとの研究に追加されている。 The Nurses’ Health Study I is an ongoing, prospective cohort study which began in 1976, enrolling female registered nurses between 30 and 55 years of age and residing in 11 US states.

BMJ 2012;345:e6390 doi: /bmj.e6390 (Published 18 October 2012)

Objective To examine the association between calcium intake and risk of primary hyperparathyroidism in women.

Design Prospective cohort study. Setting Nurses’ Health Study I, which originally recruited participants from the 11 most populous states in the United States. Participants female registered nurses enrolled in the Nurses’ Health Study I aged years in 1986 and with no history of primary hyperparathyroidism. Calcium intake was assessed every four years using semiquantitative questionnaires on food frequency. Main outcome measure Incident primary hyperparathyroidism, confirmed by medical record review.

Results During 22 years of follow-up, we recorded 277 incident cases of primary hyperparathyroidism. Women were divided into five equal groups, according to intake of dietary calcium. After adjusting for age, body mass index, race, and other factors, the relative risk of primary hyperparathyroidism for women in the group with the highest intake of dietary calcium was 0.56 (95% confidence interval 0.37 to 0.86, P=0.009 for trend), compared with the group with the lowest intake. The multivariable relative risk of primary hyperparathyroidism for women taking more than 500 mg/day of calcium supplements compared with no calcium supplements was 0.41 (95% confidence interval 0.29 to 0.60, P<0.001 for trend). Analyses restricted to participants with regular physical exams did not significantly change the association between calcium intake and risk of primary hyperparathyroidism.

Conclusion Increased calcium intake is independently associated with a reduced risk of primary hyperparathyroidism in women.

Message 米国の看護師健康調査に参加した原発性副 甲状腺機能亢進症（ PHPT ）既往のない女 性 5 万 8354 人を対象に、カルシウムと PHPT リスクの関連を前向きコホート研究 で検討。 22 年の追跡の結果、年齢や人種な どで調整後の相対リスクは、カルシウム低 摂取群に対する高摂取群で 0.56 、非摂取群 に対する 500mg/ 日摂取群で 0.41 だった。 医師研究は？

原爆傷害調査委員会（ ABCC ）

寿命調査（ Life Span Study, LSS ） 寿命調査（ LSS ）は、疫学（集団および症 例対照）調査に基づいて生涯にわたる健康 影響を調査する研究プログラムで、原爆放 射線が死因やがん発生に与える長期的影響 の調査を主な目的としています。 1950 年の 国勢調査で広島・長崎に住んでいたことが 確認された人の中から選ばれた約 94,000 人 の被爆者と、約 27,000 人の非被爆者から成 る約 12 万人の対象者を、その時点から追跡 調査しています。

BMJ 2012;345:e7093 doi: /bmj.e7093 (Published 25 October 2012)

Objective To investigate the impact of smoking on overall mortality and life expectancy in a large Japanese population, including some who smoked throughout adult life.

Design The Life Span Study, a population- based prospective study, initiated in Setting Hiroshima and Nagasaki, Japan. Participants Smoking status for men and women was obtained during Mortality from one year after first ascertainment of smoking status until 1 January 2008 has been analysed. Main outcome measures Mortality from all causes in current, former, and never smokers.

In this report we investigate the impact of smoking on overall mortality in the Life Span Study (LSS), a large cohort that is made up partly of atomic bomb survivors and and partly of a sex and age matched sample of other people who were residents of the cities of Hiroshima and Nagasaki in 1950 and born before August 1945 but who were not in the cities at the time of the bombings. Although the primary purpose of the LSS was to investigate the effects of radiation, about half the cohort members were either away from the cities at the time of the bombings or else sufficiently far away from the hypocentres of the blasts to have received exposure comparable to only one or two years of natural background radiation (that is, <5 mGy). The remaining half were exposed to whole body radiation at an average dose of 170 mGy, and it is estimated that about 3% of their deaths since 1950 are attributable to radiation.

Fig 1 Characteristics of smokers by sex and year of birth. Top: mean number of cigarettes smoked per day by current smokers (calculated as average of all reported). Bottom: mean age at which current smokers started to smoke. (Error bars show 95% confidence intervals)

Fig 2 Survival from age 35 years for Japanese men and women born between 1920 and 1945 who were never smokers or who started to smoke before age 20 years and continued smoking (mean smoking intensity among smokers of 23 cigarettes/day for men and 17 cigarettes/day for women).

Results Smokers born in later decades tended to smoke more cigarettes per day than those born earlier, and to have started smoking at a younger age. Among those born during (median 1933) and who started smoking before age 20 years, men smoked on average 23 cigarettes/day, while women smoked 17 cigarettes/day, and, for those who continued smoking, overall mortality was more than doubled in both sexes (rate ratios versus never smokers: men 2.21 (95% confidence interval 1.97 to 2.48), women 2.61 (1.98 to 3.44)) and life expectancy was reduced by almost a decade (8 years for men, 10 years for women). Those who stopped smoking before age 35 avoided almost all of the excess risk among continuing smokers, while those who stopped smoking before age 45 avoided most of it.

Conclusions The lower smoking related hazards reported previously in Japan may have been due to earlier birth cohorts starting to smoke when older and smoking fewer cigarettes per day. In Japan, as elsewhere, those who start smoking in early adult life and continue smoking lose on average about a decade of life. Much of the risk can, however, be avoided by giving up smoking before age 35, and preferably well before age 35.

Message 1950 年開始の日本の寿命調査に参加した 男性 2 万 7311 人と女性 4 万 662 人を対象に、 喫煙の寿命への影響を前向きコホート研究 で検証。 年に出生し、 20 歳前に 喫煙を開始した喫煙継続者の、非喫煙者に 対する総死亡率比は男性 2.21 、女性 2.61 だった。平均寿命も非喫煙者に比べて男性 で 8 年、女性で 10 年短かった。 35 歳までに禁煙すればまだ助かる ? これまで過小評価されていたが、 原爆の影響はともかく, タバコの影響も大きい？！