The frequency of cervical carcinoma as indicated by suspicious cervical cytologic smears and biopsy results is reported for Southwestern Indians and Caucasian residents of New Mexico, matched as closely as possible for age and socioeconomic level. Despite conditions of poverty, multiple pregnancies, early coitus, and uncircumcised consorts, Southwestern Indian women apparently have a lower rate of cervical carcinoma than age-matched Caucasian controls. The lower frequency of cervical carcinoma found in Indians is interpreted to be at least partly the result of delay in first births relative to Caucasians in the study population. Evidence is presented that delay in first pregnancies among Indians is not due to cultural factors but to a period of transient adolescent sterility. I n our study population, age at first childbirth seems to be a more significant determinant of subsequent cervical carcinoma than age at first coitus.
OST SOUTHWESTERN AMERICAN INDIAN
M women are very poor, live under primitive conditions (usually on reservations), begin coitus at an early age, and have many pregnancies. Nevertheless, preliminary studies indicate that the incidence of cervical carcinoma in these women is no higher than in other American women.l.2 Also, a study of death certificate diagnoses for Navajo Indians suggests they may have a deficit of cancer as a whole.11
The purpose of this study is to report the occurrence rate of suspicious and negative cervical papanicolaou smears in Indian women and non-Indian controls matched as closely as possible for social and economic factors. Correlation of cervical smear findings with available histologic diagnoses is also given. The data presented are derived from a prospective study which began in July 1966 and terminated June 30, 1968, and includes 18,064 women of known race.
STUDY POPULATION
Virtually all of the study population is medically indigent and includes women ex-