This is a rather old paper, but it shows very clearly that even in what is termed subclinical hypothyroidism, unhealthy levels of lipoproteins (potential harmful fats containing cholesterol) can happen. And these are mitigated by low dose T4 therapy. Haven't got a doi number but it is downloadable. It does question why, if this is a general finding with SCH, that low dose T4 isn't used to lower cholesterol levels.
Lipoprotein(a) Concentration in Subclinical Hypothyroidism Before and After Levo-Thyroxine Therapy
Metin Ozata
1996, Endocrine Journal