Excerpts from: Damrow & Murphy "Epidemiologic Profile of AIDS in Montana Prepared for HIV Community Planning " March 1999, Communicable Disease Bureau, MDPHHS
A. Executive Summary
In 1998, Acquired Immunodeficiency Syndrome (AIDS), as defined by the Centers for Disease Control and Prevention (CDC), was the eighth most common disease reported in Montana. During this period, 27 additional AIDS cases were reported, bringing the state=s cumulative total to 400 as of December 31, 1998. With thirty-nine, or 70%, of the state=s 56 counties reporting at least one AIDS case since 1985, few areas of the state have been untouched. Montana=s 1998 AIDS case rate was 2.8 (2.8 resident cases per 100,000 people), compared to 4.4 in 1997 and 3.9 in 1996. Montana=s case rate continues to be slightly higher than rates of bordering states, but significantly lower than the national average of 17.6. Montana is described as a low incidence state, reporting fewer cases of AIDS than all other states except Wyoming, and North and South Dakota. As the result of new and more effective HIV-therapies, the number of AIDS cases reported each year in the U.S. is declining. Following a similar pattern, Montana reported 40% fewer AIDS cases in 1998 than in 1997. However, it must be emphasized that the decline in AIDS cases does not indicate a similar decline in HIV-transmission. Efforts to better track HIV-trends are currently being developed and will provide a more accurate reflection of Montana=s HIV epidemic than the present AIDS reporting system.
The success of new therapies in the prevention of AIDS diagnoses has also resulted in a dramatic decrease in HIV-related deaths. As a result, the number of people living with AIDS has gradually increased, rising from 35% to 45% in the last few years. One of the leading causes of death for Montanan=s aged 25-44 in recent years, HIV infection may no longer be included in the top ten when final 1998 data are available.
AIDS continues to be reported ten times more frequently among males than females in Montana. Individuals aged 30-39 have been impacted the most, accounting for almost half of the reported cases. One-fifth of Montana AIDS cases, however, are reported among individuals in their twenties; many of whom were infected as teenagers. The overall distribution of AIDS cases among racial/ethnic groups in Montana generally reflects each groups' distribution among the total state population. Montana has not experienced the large increase in cases among racial/ethnic minority groups seen in larger urban areas of our nation.
Male-to-male sexual contact (MSM) and injecting drug use (IDU) continue to be associated with the majority of reported AIDS cases. Together, these risks account for approximately 85% of the AIDS cases occurring in Montana. Among female AIDS cases, the predominant exposure category continues to be heterosexual contact (63%). While the AIDS epidemic nationwide is increasing rapidly among injecting-drug users and among persons infected through heterosexual contact, Montana has not yet seen the relatively rapid growth of cases among these risk groups. Epidemiologic data continue to show little spread of HIV into the general population not perceived to be at high risk.
With the exception of the disproportionately low impact of AIDS in Region I (eastern Montana), the age, sex and risk factors of reported AIDS cases does not differ significantly across health planning regions. Although the characteristics of AIDS cases among American Indians also differ little from those of the general population, surrogate markers of HIV risk (teen pregnancies, STD rates) suggest an increased level of risk among American Indians when compared to non-Indian populations.
Based on the Youth Risk Behavior Survey of high school students, teens and young adults continue to represent a population at risk. Montana's youth are as sexually active as the national average. Half of those sexually involved reported not using a condom at last sexual encounter and one-third also reported being under the influence of drugs or alcohol during their last encounter.
2.1. AIDS Case Counts and Rates
As of December 31, 1998, a cumulative total of 400 cases of AIDS have been reported to the Montana Department of Public Health and Human Services (DPHHS). In 1998, Montana=s case rate (AIDS cases per 100,000 population) was 3.1 (adjusted to include non-resident cases) compared with a national rate of 17.6. When compared with 1997, the 1998 case rate for Montana and the U.S declined by approximately 20%. In Montana, this represented a decline from 47 cases reported in 1997 to 27 in 1998, and a decline in the case rate from 4.4 to 3.1 per 100,000.
The decline of AIDS reports is attributed to the success of HIV-therapies in preventing disease progression in many HIV-infected individuals. Unfortunately, a similar decline in the transmission of HIV itself has yet to be observed in national studies. At the present time, Montana=s does not have the ability to accurately track trends in HIV infection. As a result, data presented on the declining number of AIDS cases must be interpreted cautiously and supplemented with other data sources high-lighted in this report or otherwise available to community planners.
In the remainder of this report, both residents and individuals diagnosed with AIDS while living in another state who returned to or sought medical care in Montana are represented. While CDC and other federal agencies consider only resident cases in funding allocation and data analysis, DPHHS conducts surveillance and analysis on non-resident cases as well. Non-resident cases currently account for approximately 26% (105 of the 400 cases reported).
Distribution of Cases by Age, Sex and Race
The age at time of AIDS diagnosis is shown in Table 5. When analyzed by health planning region, the age distribution of cases in each individual region did not appreciably differ from the distribution noted for the state as a whole. Together, these findings show that AIDS is primarily a disease of middle-age residents, with approximately 70% of all cases in individuals aged 20 to 39. It is important to keep in mind that because of the extended incubation period of AIDS, individual cases reported to DPHHS were likely to have been infected several years previously. Of particular importance are the 85 AIDS cases in the 20-29 year-old age bracket, many of whom were infected as teenagers.
Table 5. Age at Time of AIDS Diagnosis, Montana and Health Planning Region, 1985-1998.
| Age at AIDS |
Health Planning Region | |||||
Diagnosis |
State No. (%) |
I No. (%) |
II No. (%) |
III No. (%) |
IV No. (%) |
V No. (%) |
| Under 5 Years | 4 ( 1) | 0 ( 0) | 1 ( 2) | 1 (1) | 2 ( 2) | 0 ( 0) |
| 5 - 12 Years | 0 ( 0) | 0 ( 0) | 0 ( 0) | 0 ( 0) | 0 ( 0) | 0 ( 0) |
| 13 - 19 Years | 2 ( 1) | 0 ( 0) | 1 ( 2) | 0 ( 0) | 0 ( 0) | 1 ( 1) |
| 20 - 29 Years | 85 (21) | 5 (38) | 10 (17) | 23 (23) | 19 (17) | 26 (25) |
| 30 - 39 Years | 193 (48) | 5 (38) | 28 (47) | 46 (46) | 54 (48) | 54 (51) |
| 40 - 49 Years | 76 (19) | 0 ( 0) | 14 (23) | 17 (17) | 28 (25) | 16 (15) |
| Over 49 Years | 40 (10) | 3 (23) | 6 (10) | 12 (12) | 10 ( 9) | 8 ( 8) |
| TOTAL1: | 4001 (100) | 13 (100) | 60 (100) | 99 (100) | 113 (100) | 105 (100) |
1Includes 10 cases with primary residence out of state or unknown
The distribution of Montana's reported AIDS cases by gender and by health planning region is shown in Table 6. In all regions, males are disproportionately effected. Overall, the male to female ratio of AIDS cases is approximately 9:. Among the health planning regions, M:F ratios range from 6:1 to 12:1. Analysis of AIDS cases by gender and by year of report does not show any unique trend over time. Although urban areas with large minority populations continue to report increasing numbers of AIDS cases among women, cases among Montana's women are still relatively evenly distributed over time. While Montana will continue to report AIDS cases among women, the impact of AIDS on women will be somewhat limited by Montana
=s population characteristics. Additional information on women withHIV/AIDS in Montana can be found on pages 18 and 21 of this report.2.4 Reported Risk Factors of Montana AIDS Cases
The regional distribution of AIDS cases by HIV exposure category and gender is presented in Tables 8 and 9 on the next page. State totals indicate that men who had sex with men is the predominant HIV exposure category reported, accounting for 62% of the cases in Montana men. Men who reported injecting drug use and men reporting a combination of male-to-male sexual contact and injecting drug use accounted for another 23% of reported cases. Together, male-to-male sexual contact and injecting drug use account for 85% of the AIDS cases among males in Montana.
A comparison of exposure categories by region reflects no significant differences in AIDS cases among men. The data consistently reflect approximately 80% to 90% of male cases, regardless of region, acquired infection through male-to-male sexual contact and/or injecting drug use. Although data for Region I follows this general pattern, the number of cases in any one exposure category is too small to draw reliable conclusions.
Table 8. Exposure Categories of Montana Adult/Adolescent AIDS Cases among Males, by Region, 1985-1998.
| Exposure Category- Adult/Adolescent Males |
State Total No. (%) |
Region |
||||
| I | II |
III |
IV |
V |
||
| Men who have sex w/ men | 220 (62) | 4 (36) | 29 (56) | 50 (57) | 61 (60) | 72 (74) |
| Injecting Drug Use | 43 (12) | 3 (27) | 5 (15) | 10 (11) | 12 (12) | 8 ( 8) |
| Men who have sex w/ men & inject drugs | 38 (11) | 2 (18) | 5 (10) | 13 (15) | 12 (12) | 5 ( 5) |
| Hemophilia/Coagulation disorder | 9 ( 3) | 0 ( 0) | 2 ( 4) | 3 ( 3) | 1 ( 1) | 3 ( 3) |
| Heterosexual Contact | 12 ( 3) | 1 ( 9) | 2 ( 4) | 1 ( 1) | 6 ( 6) | 2 ( 2) |
| Receipt of blood, components or tissue | 5 ( 1) | 1 ( 9) | 1 ( 2) | 1 ( 1) | 2 ( 2) | 0 ( 0) |
| Risk not Reported/Other1 | 29 ( 8) | 0 ( 0) | 5 (10) | 9 (10) | 7 ( 7) | 7 ( 7) |
| Totals: | 3562(100) | 11(100) | 52(100) | 87(100) | 101(100) | 97(100) |
| 1Refers to persons who either died during follow-up, were lost
to follow-up, or decline to be interviewed. 2 Includes cases with primary residence out of state or unknown. |
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