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Tuberculin status, socioeconomic differences and differences in all-cause mortality: experience from Norwegian cohorts born 1910-49.

Liestøl K, Tretli S, Tverdal A, Maehlen J - Int J Epidemiol (2009)

Bottom Line: Analyses were done for 10 years cohorts born 1910-49, separately for men (approximately 534,000 individuals) and women (608,000), using logistic and Cox regressions.Those infected by TB, and especially those with chest X-ray findings, have increased all-cause mortality in at least a 20 years period following determination of tuberculin status (hazard ratios approximately 1.15 and 1.30, respectively, higher for late than early cohorts).TB particularly affected lower socioeconomic strata, but even those in higher strata were at high risk.

View Article: PubMed Central - PubMed

Affiliation: Department of Informatics and Centre for Cancer Biomedicine, University of Oslo, and Department of Pathology, Ullevål University Hospital, Oslo, Norway. knut@ifi.uio.no

ABSTRACT

Background: From 1948 to 1975, Norway had a mandatory tuberculosis (TB) screening programme with Pirquet testing, X-ray examinations and BCG vaccination. Electronic data registration in 1963-75 enabled the current study aimed at revealing (i) the relations between socioeconomic factors and tuberculosis infection and (ii) differences in later all-cause mortality according to TB infection status.

Methods: TB screening data were linked to information from the Norwegian Cause of Death Registry (1975-98) and the National Population and Housing Censuses (1960, 1970 and 1980). Analyses were done for 10 years cohorts born 1910-49, separately for men (approximately 534,000 individuals) and women (608,000), using logistic and Cox regressions.

Results: TB infection and X-ray data confirmed the strong regional pattern seen for TB mortality, with the highest rates in the three northernmost counties and higher rates in urban than rural areas. High socioeconomic status relates to lower odds both for TB infection and TB-related chest X-ray findings (odds ratios 0.6-0.7 for highest vs lowest educational groups). Those infected by TB, and especially those with chest X-ray findings, have increased all-cause mortality in at least a 20 years period following determination of tuberculin status (hazard ratios approximately 1.15 and 1.30, respectively, higher for late than early cohorts).

Conclusions: TB particularly affected lower socioeconomic strata, but even those in higher strata were at high risk. The differences in all-cause mortality could partly be attributed to socioeconomic factors, but we hypothesize that developing TB infection may also indicate biological frailness.

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Related in: MedlinePlus

Left panel: Distribution of TB infected individuals, male cohort born 1910–19 (yellow: <58% infected, dark red: ≥80% infected). Right panel: TB mortality rates, male cohort born 1931–35, (yellow: ≤10 per 10 000 inhabitants, dark red: >16 per 10 000 inhabitants). White: unreliable information
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Figure 2: Left panel: Distribution of TB infected individuals, male cohort born 1910–19 (yellow: <58% infected, dark red: ≥80% infected). Right panel: TB mortality rates, male cohort born 1931–35, (yellow: ≤10 per 10 000 inhabitants, dark red: >16 per 10 000 inhabitants). White: unreliable information

Mentions: Figure 2 shows the regional distribution of TB infection and TB mortality. The distributions of TB infection are for the 1910–19 cohort, while mortality relates to 1931–35 (when average cohort age approached 20 years). The TB infection and mortality data reveal the same over-all pattern with the most serious epidemic in the north, while the southern inland have lower levels of TB infection and mortality. The same broad picture is seen for TB-related chest X-ray findings, although the distribution is more uncertain. This regional pattern is representative for cohorts born after ∼1910. Earlier the highest mortalities were found in south-western areas, while mortality has remained low in the southern inland from the earliest reliable registrations ∼1880 (Supplementary Figure 3). Incidence was lower in rural compared with urban areas, as revealed by low odds ratios for rural vs urban areas of residence [e.g. 0.68 (0.66–0.70) for men and 0.75 (0.73–0.78) for women from 1920 to 1929 cohort, Supplementary Table 1].Figure 2


Tuberculin status, socioeconomic differences and differences in all-cause mortality: experience from Norwegian cohorts born 1910-49.

Liestøl K, Tretli S, Tverdal A, Maehlen J - Int J Epidemiol (2009)

Left panel: Distribution of TB infected individuals, male cohort born 1910–19 (yellow: <58% infected, dark red: ≥80% infected). Right panel: TB mortality rates, male cohort born 1931–35, (yellow: ≤10 per 10 000 inhabitants, dark red: >16 per 10 000 inhabitants). White: unreliable information
© Copyright Policy - openaccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2663719&req=5

Figure 2: Left panel: Distribution of TB infected individuals, male cohort born 1910–19 (yellow: <58% infected, dark red: ≥80% infected). Right panel: TB mortality rates, male cohort born 1931–35, (yellow: ≤10 per 10 000 inhabitants, dark red: >16 per 10 000 inhabitants). White: unreliable information
Mentions: Figure 2 shows the regional distribution of TB infection and TB mortality. The distributions of TB infection are for the 1910–19 cohort, while mortality relates to 1931–35 (when average cohort age approached 20 years). The TB infection and mortality data reveal the same over-all pattern with the most serious epidemic in the north, while the southern inland have lower levels of TB infection and mortality. The same broad picture is seen for TB-related chest X-ray findings, although the distribution is more uncertain. This regional pattern is representative for cohorts born after ∼1910. Earlier the highest mortalities were found in south-western areas, while mortality has remained low in the southern inland from the earliest reliable registrations ∼1880 (Supplementary Figure 3). Incidence was lower in rural compared with urban areas, as revealed by low odds ratios for rural vs urban areas of residence [e.g. 0.68 (0.66–0.70) for men and 0.75 (0.73–0.78) for women from 1920 to 1929 cohort, Supplementary Table 1].Figure 2

Bottom Line: Analyses were done for 10 years cohorts born 1910-49, separately for men (approximately 534,000 individuals) and women (608,000), using logistic and Cox regressions.Those infected by TB, and especially those with chest X-ray findings, have increased all-cause mortality in at least a 20 years period following determination of tuberculin status (hazard ratios approximately 1.15 and 1.30, respectively, higher for late than early cohorts).TB particularly affected lower socioeconomic strata, but even those in higher strata were at high risk.

View Article: PubMed Central - PubMed

Affiliation: Department of Informatics and Centre for Cancer Biomedicine, University of Oslo, and Department of Pathology, Ullevål University Hospital, Oslo, Norway. knut@ifi.uio.no

ABSTRACT

Background: From 1948 to 1975, Norway had a mandatory tuberculosis (TB) screening programme with Pirquet testing, X-ray examinations and BCG vaccination. Electronic data registration in 1963-75 enabled the current study aimed at revealing (i) the relations between socioeconomic factors and tuberculosis infection and (ii) differences in later all-cause mortality according to TB infection status.

Methods: TB screening data were linked to information from the Norwegian Cause of Death Registry (1975-98) and the National Population and Housing Censuses (1960, 1970 and 1980). Analyses were done for 10 years cohorts born 1910-49, separately for men (approximately 534,000 individuals) and women (608,000), using logistic and Cox regressions.

Results: TB infection and X-ray data confirmed the strong regional pattern seen for TB mortality, with the highest rates in the three northernmost counties and higher rates in urban than rural areas. High socioeconomic status relates to lower odds both for TB infection and TB-related chest X-ray findings (odds ratios 0.6-0.7 for highest vs lowest educational groups). Those infected by TB, and especially those with chest X-ray findings, have increased all-cause mortality in at least a 20 years period following determination of tuberculin status (hazard ratios approximately 1.15 and 1.30, respectively, higher for late than early cohorts).

Conclusions: TB particularly affected lower socioeconomic strata, but even those in higher strata were at high risk. The differences in all-cause mortality could partly be attributed to socioeconomic factors, but we hypothesize that developing TB infection may also indicate biological frailness.

Show MeSH
Related in: MedlinePlus