Labour-type physical activity, metabolic dysregulation, and hypertension in rural older adults: rethinking work, exercise, and health in a cold-climate agricultural community.

Hypertension prevalence was extremely high in this rural older adult population at 75.9%.

• The study analysed 2,191 adults aged ≥65 years from a government health examination programme in a cold-climate agricultural county in Northeast China.
• The overall prevalence of hypertension was 75.9%.
• The study was a community-based cross-sectional design using routinely collected screening data.

Higher labour-type physical activity volume was associated with greater odds of prevalent hypertension compared to inactivity.

• Physical activity was quantified using a cohort-specific PA Index (weekly frequency × duration) and categorised as inactive (0), low active (0–<180), and high active (≥180; median among active participants).
• Compared with inactive participants, the odds of prevalent hypertension were higher in the low active group (OR = 1.85, 95% CI 1.32–2.58, p < 0.001).
• The high active group also showed higher odds of hypertension compared to the inactive group (OR = 2.00, 95% CI 1.61–2.49, p < 0.001).
• These associations were derived from multivariable logistic regression models that excluded blood pressure variables to avoid circularity.

Blood pressure-free obesity-metabolic phenotypes were significantly associated with hypertension prevalence.

• BP-free obesity-metabolic phenotypes were defined using BMI, triglycerides (TG), and HDL-C only, excluding any haemodynamic variables.
• Hypertension prevalence differed significantly across BP-free phenotypes (χ² = 28.07, p < 0.001).
• Hypertension prevalence ranged from 75.1% in the metabolically healthy non-obese (MHNO) group to 89.7% in the metabolically unhealthy obese (MUO) group.

A leakage-free prediction model using non-haemodynamic predictors achieved moderate discriminative performance with good calibration.

• The primary LASSO model achieved a test-set ROC-AUC of 0.664 and a PR-AUC of 0.841.
• The model demonstrated good calibration with a calibration slope of 1.10.
• The model used only routinely collected non-haemodynamic screening variables to avoid data leakage.
• The authors noted this approach may help inform outreach prioritisation and follow-up planning in resource-limited agricultural communities, pending external validation.

Labour-type physical activity in this agricultural population did not appear to replicate the cardiovascular-protective physiological stimulus of structured exercise.

• The study population consisted of older adults in a cold-climate agricultural county in Northeast China where physical activity is predominantly labour-type.
• The positive association between higher labour activity and hypertension odds is described as 'not consistent with the assumption that work equals exercise.'
• The authors note that evidence remains limited regarding how labour intensity relates to hypertension in cold-climate rural populations.
• The cross-sectional design precludes causal inference about the direction of the relationship between labour activity and hypertension.