Title Longitudinal Patterns of Stages of Change for Exercise and Lifestyle Intervention Outcomes : An Application of Latent Class Analysis with Distal Outcomes Permalink

Stages of change measure an individual's readiness to alter a health behavior. This study examined the latent longitudinal patterns of stages of change (SoC) for regular exercise over time among individuals participating in a lifestyle intervention project. It also investigated the association between the longitudinal patterns of SoC and intervention outcomes using a new statistical method to assess the relationship between latent class membership and distal outcomes. We analyzed data from the Special Diabetes Program for Indians Diabetes Prevention Program, a lifestyle intervention program to prevent diabetes among American Indians and Alaska Natives. Latent class analysis (LCA) was conducted to identify the longitudinal patterns of SoC for regular * Address for Correspondence and Reprints, Luohua Jiang, Department of Epidemiology, University of California Irvine, 205B Irvine Hall, Irvine, CA 92697-7550, lhjiang@uci.edu, Tel: 949-824-7325. **Grant programs participating in the Special Diabetes Program for Indians Diabetes Prevention Demonstration Project: Confederated Tribes of the Chehalis Reservation, Cherokee Nation, Cheyenne River Sioux Tribe, the Chickasaw Nation, Coeur d'Alene Tribe, Colorado River Indian Tribes, Colville Confederated Tribes, Cow Creek Band of Umpqua Tribe, Fond du Lac Reservation, Gila River Health Care, Haskell Health Center, Ho-Chunk Nation, Indian Health Board of Minneapolis, Urban Native Diabetes Prevention Consortium, Kenaitze Indian Tribe IRA, Lawton IHS Service Unit, Menominee Indian Tribe of Wisconsin, Mississippi Band of Choctaw Indians, Norton Sound Health Corporation, Pine Ridge IHS Service Unit, Pueblo of San Felipe, Quinault Indian Nation, Rapid City IHS Diabetes Program, Red Lake Comprehensive Health Services, Rocky Boy Health Board, Seneca Nation of Indians, Sonoma County Indian Health Project, South East Alaska Regional Health Consortium, Southcentral Foundation, Trenton Indian Service Area, Tuba City Regional Health Care Corporation, United American Indian Involvement, Inc., United Indian Health Services, Inc., Warm Springs Health & Wellness Center, Winnebago Tribe of Nebraska, Zuni Pueblo. COMPLIANCE WITH ETHICAL STANDARDS Disclosure of potential conflicts of interest: The authors claim no conflict of interest. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The SDPI-DP protocol was approved by the institutional review board (IRB) of the University of Colorado Denver and the IHS IRB. When required, grantees obtained approval from other entities charged with overseeing research in their programs (e.g., tribal review boards). Informed consent. All participants provided written informed consent and Health Insurance Portability and Accountability Act authorization. HHS Public Access Author manuscript Prev Sci. Author manuscript; available in PMC 2017 April 01. Published in final edited form as: Prev Sci. 2016 April ; 17(3): 398–409. doi:10.1007/s11121-015-0599-y. A uhor M anscript