Browsing by Subject "confounding factors"

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  • Pylväläinen, Juho; Talala, Kirsi; Murtola, Teemu; Taari, Kimmo; Raitanen, Jani; Tammela, Teuvo L.; Auvinen, Anssi (2019)
    Purpose: To evaluate the performance of Charlson Comorbidity Index (CCI) calculated using hospitalization and medication reimbursement databases in predicting mortality. Patients and methods: Information on hospitalizations was obtained from the national Care Register for Health Care (HILMO) and on medication reimbursements and entitlements for special reimbursements for medications from the Social Insurance Institution for 77,440 men aged 56-71 years at baseline. The subjects were followed up for mortality via Statistics Finland with 20,562 deaths during a 13-year follow-up. Results: Compared to a CCI score of 0, the age-adjusted hazard ratio for all-cause mortality associated with HILMO-based CCI scores of 1, 2 and 3 or more were 2.39 (95% CI 2.29-2.49), 2.96 (95% CI 2.81-3.13) and 6.42 (95% CI 5.95-6.93) at 13 years. The C-statistic was 0.72 at 1, 0.68 at 5 and 0.66 at 13 years, with only minor improvement over age alone (0.10, 0.06 and 0.04 accordingly). Addition of medication data did not improve predictive abilities and medication-based CCI performed poorly on its own. Conclusion: The hospitalization-based CCI, as well as that based on both databases, predicts relative mortality adequately, but its discriminative ability diminishes over time. Conditions related to hospitalizations affect survival more than medications.
  • Sipila, Pyry; Rose, Richard J.; Kaprio, Jaakko (2016)
    AimsTo determine if associations of alcohol consumption with all-cause mortality replicate in discordant monozygotic twin comparisons that control for familial and genetic confounds. DesignA 30-year prospective follow-up. SettingPopulation-based older Finnish twin cohort. ParticipantsSame-sex twins, aged 24-60years at the end of 1981, without overt comorbidities, completed questionnaires in 1975 and 1981 with response rates of 89 and 84%. A total of 15607 twins were available for mortality follow-up from the date of returned 1981 questionnaires to 31December 2011; 14787 twins with complete information were analysed. MeasurementsSelf-reported monthly alcohol consumption, heavy drinking occasions (HDO) and alcohol-induced blackouts. Adjustments for age, gender, marital and smoking status, physical activity, obesity, education and social class. FindingsAmong twins as individuals, high levels of monthly alcohol consumption (259g/month) associated with earlier mortality [hazard ratio (HR)=1.63, 95% confidence interval (CI)=1.47-1.81]. That association was replicated in comparisons of all informatively drinking-discordant twin pairs (HR=1.91, 95% CI=1.49-2.45) and within discordant monozygotic (MZ) twin pairs (HR=2.24, 95% CI=1.31-3.85), with comparable effect size. Smaller samples of MZ twins discordant for HDO and blackouts limited power; a significant association with mortality was found for multiple blackouts (HR=2.82, 95% CI=1.30-6.08), but not for HDO. ConclusionsThe associations of high levels of monthly alcohol consumption and alcohol-induced blackouts with increased all-cause mortality among Finnish twins cannot be explained by familial or genetic confounds; the explanation appears to be causal.
  • Barbuscia, Anna; Martikainen, Pekka; Myrskylä, Mikko; Remes, Hanna; Somigliana, Edgardo; Klemetti, Reija; Goisis, Alice (2020)
    STUDY QUESTION Does the risk of low birth weight and premature birth increase with age among mothers who conceive through medically assisted reproduction (MAR)? SUMMARY ANSWER Among MAR mothers, the risk of poorer birth outcomes does not increase with maternal age at birth except at very advanced maternal ages (40+). WHAT IS KNOWN ALREADY The use of MAR treatments has been increasing over the last few decades and is especially diffused among women who conceive at older ages. Although advanced maternal age is a well-known risk factor for adverse birth outcomes in natural pregnancies, only a few studies have directly analysed the maternal age gradient in birth outcomes for MAR mothers. STUDY DESIGN, SIZE, DURATION The base dataset was a 20% random sample of households with at least one child aged 0-14 at the end of 2000, drawn from the Finnish population register and other administrative registers. This study included children who were born in 1995-2000, because the information on whether a child was conceived through MAR or naturally was available only from 1995 onwards. PARTICIPANTS/MATERIALS, SETTING, METHODS The outcome measures were whether the child had low birth weight (LBW, MAIN RESULTS AND THE ROLE OF CHANCE A total of 56026 children, 2624 of whom were conceived through MAR treatments, were included in the study. Among the mothers who used MAR to conceive, maternal age was not associated with an increased risk of LBW (the overall prevalence was 12.6%) at ages 25-39. For example, compared to the risk of LBW at ages 30-34, the risk was 0.22 percentage points lower (95% CI: -3.2, 2.8) at ages 25-29 and was 1.34 percentage points lower (95% CI: -4.5, 1.0) at ages 35-39. The risk of LBW was increased only at maternal ages >= 40 (six percentage points, 95% CI: 0.2, 12). Adjustment for maternal characteristics only marginally attenuated these associations. In contrast, among the mothers who conceived naturally, the results showed a clear age gradient. For example, compared to the risk of LBW (the overall prevalence was 3.3%) at maternal ages 30-34, the risk was 1.1 percentage points higher (95% CI: 0.6, 1.6) at ages 35-39 and was 1.5 percentage points higher (95% CI: 0.5, 2.6) at ages >= 40. The results were similar for preterm births. LIMITATIONS, REASON FOR CAUTION A limited number of confounders were included in the study because of the administrative nature of the data used. Our ability to reliably distinguish mothers based on MAR treatment type was also limited. WIDER IMPLICATIONS OF THE FINDINGS This is the first study to analyse the maternal age gradient in the risk of adverse birth outcomes among children conceived through MAR using data from a nationally representative sample and controlling for important maternal health and socio-economic characteristics. This topic is of considerable importance in light of the widespread and increasing use of MAR treatments.
  • Moustgaard, Heta; Avendano, Mauricio; Martikainen, Pekka (2018)
    Parental unemployment is associated with worse adolescent mental health, but prior evidence has primarily been based on cross-sectional studies subject to reverse causality and confounding. We assessed the association between parental unemployment and changes in adolescent psychotropic medication purchases, with longitudinal individual-level fixed-effects models that controlled for time-invariant confounding. We used data from a large, register-based panel of Finnish adolescents aged 13–20 years in 1987–2012 (n = 138,644) that included annual measurements of mothers’ and fathers’ employment and offspring psychotropic medication purchases. We assessed changes in the probability of adolescent psychotropic medication purchases in the years before, during, and after the first episode of parental unemployment. There was no association between mother’s unemployment and offspring psychotropic purchases in the fixed-effects models, suggesting this association is largely driven by unmeasured confounding and selection. By contrast, father’s unemployment led to a significant 15%–20% increase in the probability of purchasing psychotropic medication among adolescents even after extensive controls for observed and unobserved confounding. This change takes at least 1 year to emerge, but it is long-lasting; thus, policies are needed that mitigate the harm of father’s unemployment on offspring’s mental well-being.