Age-Related Variations in Body Composition and Metabolic Health: A Cross-Sectional Study in Adults.

Adults aged 40-49 had a significantly worse metabolic profile than younger individuals, including higher total cholesterol, LDL cholesterol, triglycerides, and glucose.

• Cross-sectional study included 169 adults (60 men and 109 women) aged 36.30 ± 6.25 years, grouped into <30, 30-39, and 40-49 year age groups.
• Statistically significant higher total cholesterol, LDL cholesterol, triglycerides, and glucose were observed in the 40-49-years group compared to younger groups.
• In women aged 40-49, a more adverse lipid and glycemic profile was observed compared to younger groups.
• Participants were assessed for fasting lipids, inflammation markers, body composition, and platelet fatty acids.

Fat mass and its regional distribution were higher after age 40, with sex-specific patterns of fat accumulation across age groups.

• Fat mass and regional fat distribution were higher after age 40, especially in females.
• In women, fat mass was lower in the thirties and higher again in the forties, while in men fat accumulation was progressive across age groups.
• Fat mass strongly correlated with insulin resistance, triglycerides, and CRP, and inversely with HDL-C.
• Body composition assessments covered fat mass, fat distribution, and lean mass.

Malondialdehyde levels, a marker of oxidative stress, were significantly higher in the 40-49 age group compared to the 30-39 age group.

• Malondialdehyde was higher in the 40-49-years group vs. the 30-39-years group (105.83 vs. 99.72, p = 0.034).
• Malondialdehyde was used as a measure of oxidative stress in this study.
• This finding suggests increasing oxidative stress as a feature of metabolic deterioration in the fifth decade of life.

Platelet polyunsaturated fatty acids and ω6 fatty acid percentages were significantly higher in the 40-49 age group compared to younger groups.

• Polyunsaturated fatty acids percentage was higher in the 40-49 group vs. younger groups (12.85% vs. 10.14%, p = 0.046).
• ω6 fatty acid percentage was higher in the 40-49 group vs. younger groups (11.44% vs. 8.79%, p = 0.031).
• Linoleic acid was higher in the 40-49 group (8.80 ± 5.18 vs. 6.97 ± 5.05, p = 0.045).
• Arachidonic acid was higher in the 40-49 group (2.64 ± 2.64 vs. 1.82 ± 1.73, p = 0.030).
• Docosahexaenoic acid was higher in the 40-49 group (0.61 ± 0.86 vs. 0.31 ± 0.49, p = 0.008).

The fifth decade of life was identified as a transitional period characterized by central adiposity, deteriorating metabolic profiles, and altered fatty acid composition, particularly in women.

• Women aged 40-49 showed a more adverse lipid and glycemic profile compared to younger groups.
• Central adiposity was identified as a key feature of the metabolic transition occurring after age 40.
• Gender-specific patterns were observed across body composition, metabolic biomarkers, and fatty acid profiles.
• Midlife was described as 'a critical window for the emergence of metabolic risk factors.'