Page 84 - JCBP-3-1

Journal of Clinical and
Basic Psychosomatics HDL markers and suicidal ideation

2.4. Covariates who reported having smoked ≥100 cigarettes in their

To account for potential confounders in the association lifetime were classified as smokers
between HDL-related inflammatory indicators and SI, (ii) Alcohol consumption: Alcohol consumption was
several covariates were adjusted based on previous studies categorized as “No” or “Yes” based on responses to
and available NHANES data. These covariates were the NHANES questions “ALQ101” and “ALQ111.”
8,21
carefully selected to control for demographic, lifestyle, Participants who reported consuming more than
and health-related variables that could influence both a 12-ounce beer, a 5-ounce serving of wine, or 1.5
inflammation and SI, thereby ensuring the validity and ounces of liquor were classified as alcohol consumers.
robustness of our findings. 2.4.3. Health condition variables

2.4.1. Demographic variables (i) Hypertension: Hypertension was identified through
a combination of self-reported physician diagnoses,
(i) Age group: Age was categorized into three groups (20 systolic blood pressure ≥140 mmHg, diastolic blood
– 39, 40 – 64, or ≥65) to explore potential age-related
heterogeneity in the association between HDL-related pressure ≥90 mmHg, or the use of antihypertensive
inflammatory indicators and SI. Age was recorded in medication
NHANES using the variable “RIDAGEYR,” reported (ii) Diabetes: Diabetes was identified based on self-
in years. This categorization allowed us to investigate reported physician diagnoses, an A1c level ≥6.5%,
whether certain age cohorts exhibited stronger the use of insulin or diabetes medications, fasting
or weaker associations with SI, considering that glucose levels ≥7.0 mmol/L, random glucose levels
inflammation and lipid metabolism may vary by age. >11.1 mmol/L, or oral glucose tolerance test results
In addition, SI has been shown to differ significantly ≥11.1 mmol/L
across age groups, necessitating this stratification (iii) Stroke: Stroke was identified based on participants’
(ii) Gender: Gender (female or male) was determined responses to the NHANES question “MCQ160f,”
using the NHANES variable “RIAGENDR.” Given the which asked whether they had been previously
known differences in both suicide rates and biological diagnosed with a stroke by a doctor or other health-
responses to inflammation between men and women, care professional
gender was an essential covariate. Previous studies have (iv) Kidney disease: Kidney disease was identified using
demonstrated that women tend to exhibit higher rates the NHANES question “KIQ022,” which asked
participants if they had been diagnosed with weak or
of SI but lower rates of completed suicide compared to
men, potentially due to biological, psychological, and failing kidneys by a physician.
social factors 2.5. Statistical analysis
(iii) Race: Race was categorized into five groups – other
Hispanic, non-Hispanic Black, non-Hispanic White, A weighting strategy (WTMEC2YR) was employed to
Mexican American, and other race – as captured by strengthen the reliability of our results while examining
the NHANES variable “RIDRETH1” the relationship between HDL-related inflammatory
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(iv) Marital status: Marital status was classified into markers and SI. For continuous variables, data were
three categories – married/living with a partner, reported as weighted medians with interquartile ranges,
separated/divorced/widowed, and never married – and differences between groups were analyzed using
using the NHANES variables “DMDMARTL” and the weighted Wilcoxon rank-sum test. For categorical
“DMDMARTZ” variables, data are presented as weighted percentages,
(v) Education level: Educational attainment was grouped and differences among groups were evaluated using the
into three levels – less than high school, high school, weighted Chi-square test. In addition, Spearman’s rank
and greater than high school – using the NHANES correlation was used to assess associations among the
variables “DMDEDUC2” and “DMDEDUC3” different inflammatory markers.
(vi) PIR: Socioeconomic status, as measured using the PIR, Weighted logistic regression was performed to analyze
was categorized into three groups – <1.3, 1.3 – 3.5, and the association between HDL-related inflammatory
≥3.5 – using the NHANES variable “INDFMPIR.” indicators and SI, categorizing these indicators into tertiles
to strengthen the robustness of our conclusions. Weighted
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2.4.2. Lifestyle variables restricted cubic spline (RCS) analysis with three-knot points
(i) Smoking status: Smoking status was determined based was used to investigate the dose–response relationship
on responses to the NHANES question “SMQ020.” between HDL-related inflammatory indicators and SI.
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Participants were categorized as “Yes” or “No.” Those To address the high correlations among inflammatory

Volume 3 Issue 1 (2025) 78 doi: 10.36922/jcbp.5084