Patterns of Cigarette Smoking Initiation in Two Culturally Distinct American Indian Tribes

Objectives. To better understand patterns of initiation among American Indians we examined age-related patterns of smoking initiation during adolescence and young adulthood in 2 American Indian tribes. Methods. We used log-rank comparison and a Cox proportional hazard regression model to analyze data from a population-based study of Southwest and Northern Plains American Indians aged 18 to 95 years who initiated smoking by age 18 years or younger.Results. The cumulative incidence of smoking initiation was much higher among the Northern Plains Indians (47%) than among the Southwest Indians (28%; P < .01). In the Southwest, men were more likely than women to initiate smoking at a younger age (P < .01); there was no such difference in the Northern Plains sample. Northern Plains men and women in more recent birth cohorts initiated smoking at an earlier age than did those born in older birth cohorts. Southwest men and women differed in the pattern of smoking initiation across birth cohorts as evidenced by the significant test for interaction (P = .01).Conclusion. Our findings underscore the need to implement tobacco prevention and control measures within American Indian communities.Smoking rates in the US population have declined overall in the past several decades, from a high of 42% in 1960 to an estimate of 21% in 2007.¹ However, this decline has not been observed among all racial/ethnic groups nor among all age groups. The prevalence of smoking among American Indians and Alaska Natives, for example, is greater than 50% in many communities, roughly 2.5 times the prevalence in the US general population.^2–7 Furthermore, over the past 3 decades, rates of smoking have been rising in some tribal communities that have historically low rates,^2,8 roughly paralleling the increases in smoking-related diseases, including lung cancer and respiratory and cardiovascular diseases, in American Indians and Alaska Natives.^9,10 Smoking also contributes to the observation that American Indians and Alaska Natives trail only African Americans in years of potential life lost,¹¹ a key indicator of population health. Finally, adverse health outcomes associated with smoking are adding inordinately high health care costs to a dramatically underfunded Indian Health Service.¹²One of the key factors linked to nicotine dependence is age of smoking initiation. Studies have shown that an earlier age of smoking initiation is related to current and daily smoking^13,14 and that the transition from smoking initiation to established smoking generally takes 2 to 3 years.^15,16 However, a more recent study among a cohort of sixth graders reported that youth were susceptible to a rapid loss of autonomy over tobacco. This occurred within 1 or 2 days of first inhalation, and dependency was likely to appear before reaching a consumption rate of 2 cigarettes per day.¹⁷ In addition, smokers who begin smoking at younger ages are more likely than those starting later to develop nicotine dependence, thus making quitting more difficult.^13,14,18Studies among African Americans have revealed major declines in smoking prevalence among adolescents during the 1980s, which were offset by increased initiation among young adults during this period.¹⁹ Such data helped to enhance public health efforts to promote cessation and discourage initiation among African Americans. However, little is known about patterns of smoking initiation among American Indians and Alaska Natives. In a recent survey of South Dakota high school students, more than 45% of American Indian adolescents who were smoking reported starting to smoke before the age of 13 years.²⁰ To better understand the patterns of smoking initiation among American Indians, we conducted a study that examined the age of smoking initiation in 2 culturally distinct American Indian tribal groups across birth cohorts.     

Determination of the solute removal index for urea by using a partial spent dialysate collection method

In 22 hemodialysis patients, during a dialysis session, the solute removal index (SRI) for urea obtained from the use of a partial spent dialysate collection method was compared with that derived from the use of a total spent dialysate collection technique. The partial spent dialysate collection method was used to harvest a small representative sample of the total spent dialysate. The volumes of spent dialysate collected by the partial and the total spent dialysate collection methods were 1.7 +/- 0.4 L and 129.6 +/- 15.3 L, respectively. The total amount of urea nitrogen removed by dialysis as estimated by the partial spent dialysate collection method was similar to that determined by the total spent dialysate collection approach. As a result, the SRI value for urea obtained by the partial spent dialysate collection method (namely, 63% +/- 8%) correlated very well (r = 0.95, P < 0.001) with that derived by the total spent dialysate collection technique (namely, 62% +/- 8%). Our data suggest that it is feasible to use a simple partial spent dialysate collection method to obtain SRI results in patients treated with hemodialysis.